Stratno | Stratigraphic Name | Category | Contents | Last update 
24161|Annakananda Formation|Name source|Annakananda, a large cave system leading from sinkhole at DN 543463, Wedge 1:100 000 Map sheet.|16-MAY-23
24161|Annakananda Formation|Type section locality|Approximately 30m of conglomerate and lithic sandstone exposed on southern wall of sinkhole [DN 543463]|16-MAY-23
24161|Annakananda Formation|Extent|A relatively thin (30-100 m) unit exposed over a strike length of approximately 3 km in the Mt Anne-Lake Timk area. A thinner correlate is intermittently exposed between the Weld River and the South Styx River (Tyenna 1:100 000 Map sheet).|16-MAY-23
24161|Annakananda Formation|Thickness range|0-approximately 100 m|16-MAY-23
24161|Annakananda Formation|Lithology|Predominantly closed-framework, pebble-cobble conglomerate, usually reddish in colour, and red to brown lithic sandstone. Correlates east of Weld River are predominantly red mudstone, with minor conglomerate.|16-MAY-23
24161|Annakananda Formation|Relationships and boundaries|Oldest unit of Weld River Group. Unconformably overlies Pandani Group (Precambrian) in type area. Conformably overlain by Gomorrah Dolomite.|16-MAY-23
24161|Annakananda Formation|Age reasons|Late Precambrian (as for Weld River Group).|16-MAY-23
40973|Bird Phyllite|Name source|Bird Road (crosses unit); Bird Creek (wholly within unit).|16-MAY-23
40973|Bird Phyllite|Unit history|First used informally by Everard (1999). Equivalent to part of the Keith Metamorphics (ASUD: superseded) of Gee (1966, 1971, 1977), Gee et al. (1967).|16-MAY-23
40973|Bird Phyllite|Constituents|Includes unnamed schistose quartzite units, mapped in Lapoinya area.|16-MAY-23
40973|Bird Phyllite|Geomorphic expression|Drainage usually deeply incised. Less resistant than the adjacent Jacob Quartzite.|16-MAY-23
40973|Bird Phyllite|Type section locality|The type section is specified as the Arthur River, from a point 250 m downstream of the site of Hilders Bridge (366500mE, 5445850mN) to a point ~4 km upstream (367500mE, 5442870mN).|16-MAY-23
40973|Bird Phyllite|Extent|Extends from near Moorleah (~382888mE, 5460800mN) generally SW for ~31 km to the upper Eastons Creek area (~ 361000mE, 5439000mN). Possibly extends further SW to the upper Rapid River area (358000mE, ~5432500mN).|16-MAY-23
40973|Bird Phyllite|Thickness range|2.5 km (apparent). Stratigraphic thickness is difficult to estimate due to deformation.|16-MAY-23
40973|Bird Phyllite|Lithology|Dominantly dark grey to grey-green phyllite, with lesser pelitic schist, foliated quartzarenite and well-bedded dolostone. Basal siliciclastic cobble-pebble conglomerate observed outside type section (e.g. ~362900mE, 5441350mN; 359300mE, 5437200mN).|16-MAY-23
40973|Bird Phyllite|Depositional environment|Likely protolith is shallow marine shelf sediments.|16-MAY-23
40973|Bird Phyllite|Fossils|Not known.|16-MAY-23
40973|Bird Phyllite|Diastems or hiatuses|Not known.|16-MAY-23
40973|Bird Phyllite|Relationships and boundaries|To the NW: overlies the Jacob Quartzite, probably with low angle unconformity and local development of basal siliciclastic conglomerate. To the SE: structurally overlain to the SE by the Champion Schist, contact concordant but nature uncertain, possibly conformable, faulted or transitional (as shown on MRT 1:25000 maps). Concealed by Cainozoic basalt +/- sub-basalt gravels) in places, including at its northernmost known exposure.|16-MAY-23
40973|Bird Phyllite|Identifying features|Typically dark grey phyllite/schist; cleavage dominant, crenulation cleavage common; intercalated carbonate and quartzarenite; less schistose and less chloritic (less green) than the adjoining Champion Schist.|16-MAY-23
40973|Bird Phyllite|Structure and Metamorphism|Strong (usually steeply NW-dipping) penetrative cleavage, crenulation cleavage also commonly present. Talc identified in some dolostone samples.|16-MAY-23
40973|Bird Phyllite|Age reasons|Neoproterozoic, late Tonian or Early Cryogenian.  Youngest concordant detrital zircon 769 ±5 Ma (LA-ICPMS zircon; Mulder et al., in prep.)|16-MAY-23
40973|Bird Phyllite|Correlations|Possible metamorphosed equivalent of the lower Togari Group, lower Ahrberg Group and Success Creek Formation.|16-MAY-23
40973|Bird Phyllite|Alteration and Mineralisation|Not known.|16-MAY-23
40973|Bird Phyllite|Geophysical Expression|Radiometrics: Higher counts than adjacent units (Jacob Quartzite, Champion Schist, Cainozoic basalt); K-dominant (pinkish RGB hue). Magnetics- usually weakly magnetic with bland signature, with moderately intense strike-parallel anomalies in some areas.|16-MAY-23
40973|Bird Phyllite|Geochemistry|Pelitic to dolomitic. See Sample R004998/AR489 (MRT TIGER database) for a possibly representative analysis (includes SiO2 65.2%, Al2O3 8.5%, FeOt 4.0%, MgO 4.4%, CaO 4.6%, Na2O 0.1%, K2O 3.9%, CO2 7.5%, H2O+ 0.9%).|16-MAY-23
40973|Bird Phyllite|Defn author|Everard, J.L. 16-SEP-2019.|16-MAY-23
40973|Bird Phyllite|Comments|Corresponds to units Pap, Papc and Papd on Trowutta 1:50000 map sheet (Everard et al. 1996).  Corresponds to units Pap, Papc, Papd and Papq on MRT Digital Geological Atlas 1:25000 series.   Corresponds to units Pkp ("Phyllite-marginal to metamorphics") and Pkq ("Schistose quartzite") on the Burnie 1:63360 sheet (Gee et al. 1967).|16-MAY-23
40973|Bird Phyllite|References|CUMMING G. V. & JACKMAN C.J. 2018. Digital Geological Atlas 1:25000 series. Sheet 3643. Keith. Mineral Resources Tasmania.  **EVERARD J. L. (COMP.) 1998. Digital Geological Atlas 1:25000 series. Sheet 3845. Calder. Mineral Resources Tasmania.  **EVERARD J. L., SEYMOUR D. B. & BROWN A. V. 1996. Geological Atlas 1:50,000 Series, Sheet 27 (7915N). Trowutta. Mineral Resources Tasmania.  **EVERARD J. L. 1999. A blue amphibole occurrence from the Flowerdale River, northern Arthur Lineament. Tasmanian Geological Survey Record 1999/05. 19 pp.  **GEE R. D.1966. Geological Atlas 1 Mile Series, Sheet 22 (8016S). Table Cape. Tasmania Department of Mines.  **GEE R. D. 1971. Geological Atlas 1 Mile Series, Sheet 22 (8016S). Table Cape. Geol. Survey Explan. Rept., Tasmania Dept. of Mines.  **GEE R. D. 1977: Burnie, Tasmania. Tasm. Dep. Mines Geol. Atlas 1 Mile Series Expl. Rep., Sheet 22 (8015N).  **GEE R. D., GULLINE A. B. & BRAVO A. P. 1967. Geological Atlas 1:63,360 Series, Sheet 28 (8015N). Burnie. Tasmania Department of Mines.  **MULDER  J. A & EVERARD J.L., CUMMING G.V., MEFFRE S., BOTTRILL R.S., MERDITH A.S., HALPIN J.A. MCNEILL A, & CAWOOD P.A. Neoproterozoic opening of the Pacific Ocean recorded by multi-stage rifting in Tasmania. Submitted to Earth Science Reviews.  **SEYMOUR D. B. (COMP.) 1998. Digital Geological Atlas 1:25000 series. Sheet 3645. Milabena. Mineral Resources Tasmania.  **SEYMOUR D. B. & EVERARD J.L. 1998. Digital Geological Atlas 1:25000 series. Sheet 3644. Folly. Mineral Resources Tasmania.|16-MAY-23
79056|Champion Schist|Name source|Champion Road (mostly within unit).|16-MAY-23
79056|Champion Schist|Unit history|First used informally by Everard (1999). Briefly mentioned by Corbett et al. (2014), p. 70, 78.Equivalent to part of the Keith Metamorphics (ASUD: superseded) of Gee (1966, 1971, 1977), Gee et al. (1967).
|16-MAY-23
79056|Champion Schist|Constituents|Includes mappable amphibolite bodies [presumably unnamed at this time].|16-MAY-23
79056|Champion Schist|Geomorphic expression|Mostly deeply incised drainage (similar to Bird Phyllite).|16-MAY-23
79056|Champion Schist|Type section locality|The type section is specified as exposures in the Arthur River, between (367500mE, 5442870mN) and Tiger Bend (368200mE, 5440450mN).|16-MAY-23
79056|Champion Schist|Extent|Extends SW from Moorleah (~384600mE, 5461700mN) for ~33 km to the upper Pinner Creek area (~363000mE, 5436200mN). Small outcrops exposed in the Inglis River near Wynyard (~390800mE, 5463400mN) are probable correlates.|16-MAY-23
79056|Champion Schist|Thickness range|~ 2.2 km (apparent) in the type area; up to 4.5 km (apparent) in the Flowerdale River area. Stratigraphic thickness is difficult to estimate due to deformation.|16-MAY-23
79056|Champion Schist|Lithology|Chloritic schist, with minor pelitic schist, phyllite, dolomite and magnesite, and +/-concordant amphibolite bodies.|16-MAY-23
79056|Champion Schist|Depositional environment|Likely protolith is dominantly mafic volcaniclastics, probably deposited in a shallow marine environment.|16-MAY-23
79056|Champion Schist|Fossils|Not known.|16-MAY-23
79056|Champion Schist|Diastems or hiatuses|Not known.|16-MAY-23
79056|Champion Schist|Relationships and boundaries|To the  NW: structurally overlies the Bird Phyllite, concordant contact of uncertain nature, possibly conformable, faulted or transitional (as shown on MRT 1:25000 maps). To the SE: faulted against or overlain with landscape unconformity by the Inglis Siltstone. Locally capped by Cainozoic basalt.|16-MAY-23
79056|Champion Schist|Identifying features|Schistose fabric, dark green hue, brown-weathering, presence of amphibolite bodies and lack of quartzarenite beds usually distinguishes the unit from the Bird Phyllite. Weathers to a deep brown soil.|16-MAY-23
79056|Champion Schist|Structure and Metamorphism|Schistose fabric, usually steeply NW-dipping. Local crenulation cleavage and tight to isoclinal refolding of dominant foliation. Intercalated amphibolites usually with low grade (greenschist facies) albite-epidote-chlorite-actinolite-titanite assemblages, possibly retrograde; sodic amphibole indicative of earlier high pressure (>/=560 MPa) blueschist facies conditions is preserved in an amphibolite in the Flowerdale River (Everard 1999).|16-MAY-23
79056|Champion Schist|Age reasons|Neoproterozoic, probably late Cryogenian or early Ediacaran (from likely correlates).|16-MAY-23
79056|Champion Schist|Correlations|Possible correlate on lithological grounds with the middle Togari Group (Kanunnah Subgroup), middle Ahrberg Group and/or Crimson Creek Formation.|16-MAY-23
79056|Champion Schist|Alteration and Mineralisation|Anomalous copper (0.65%) and malachite is noted in an intercalated amphibolite from the Lyons River (R005415/KJ120B, MRT TIGER database).|16-MAY-23
79056|Champion Schist|Geophysical Expression|Radiometrics: Lower total counts than Bird Phyllite and Inglis Siltstone; slightly higher total counts than Cainozoic basalt; K-dominant (pinkish RGB hue). Magnetics- moderately to strongly positive with NE-trending grain; TMI increases to SE (up section) in Arthur R area.|16-MAY-23
79056|Champion Schist|Geochemistry|A representative sample of schist (R004992/AR471) has a basaltic composition (e.g. SiO2 51.4%, FeOt 10.4%, MgO 7.0%; MRT TIGER database). Intercalated amphibolites are strongly fractionated, probably continental rift tholeiites (Everard 1999; Calver & Everard in Corbett et al. 2017, p. 77-78).|16-MAY-23
79056|Champion Schist|Defn author|Everard, J.L., 16-SEP-2019.|16-MAY-23
79056|Champion Schist|Proposed publication|Keith, Folly, Milabena, Calder, Wynyard 1:25000 maps (to be amended).|16-MAY-23
79056|Champion Schist|Comments|Corresponds to units Pac and Paa on the Trowutta 1:50000 map sheet (Everard et al. 1996) and units Pac, Pacp and Paa on MRT Digital Geological Atlas 1:25000 series. Corresponds to ¿Pks- pelitic, calcic and basic schists¿ within Keith Metamorphics on the Burnie 1:63360 sheet (Gee et al. 1967).|16-MAY-23
79056|Champion Schist|References|CUMMING G. V. & JACKMAN C.J. 2018. Digital Geological Atlas 1:25000 series. Sheet 3643. Keith. Mineral Resources Tasmania.  **EVERARD J. L. (COMP.) 2004. Digital Geological Atlas 1:25000 series. Sheet 3845. Calder. Mineral Resources Tasmania.  **EVERARD J. L., SEYMOUR D. B. & BROWN A. V. 1996. Geological Atlas 1:50,000 Series, Sheet 27 (7915N). Trowutta. Mineral Resources Tasmania.  **EVERARD J. L. 1999. A blue amphibole occurrence from the Flowerdale River, northern Arthur Lineament. Tasmanian Geological Survey Record 1999/05. 19 pp.  **CORBETT, K. D.; QUILTY, P. G. & CALVER, C. R. 2014. Geological Evolution of Tasmania. Geological Society of Australia Special Publication 24.  **GEE R. D.1966. Geological Atlas 1 Mile Series, Sheet 22 (8016S). Table Cape. Tasmania Department of Mines.  **GEE R. D. 1971. Geological Atlas 1 Mile Series, Sheet 22 (8016S). Table Cape. Geol. Survey Explan. Rept., Tasmania Dept. of Mines.  **GEE R. D. 1977: Burnie, Tasmania. Tasm. Dep. Mines Geol. Atlas 1 Mile Series Expl. Rep., Sheet 22 (8015N).  **GEE R. D., GULLINE A. B. & BRAVO A. P. 1967. Geological Atlas 1:63,360 Series, Sheet 28 (8015N). Burnie. Tasmania Department of Mines.  **SEYMOUR D. B. (COMP.) 1998. Digital Geological Atlas 1:25000 series. Sheet 3645. Milabena. Mineral Resources Tasmania.  **SEYMOUR D. B. & EVERARD J.L. 1998. Digital Geological Atlas 1:25000 series. Sheet 3644. Folly. Mineral Resources Tasmania.|16-MAY-23
74595|City of Melbourne Volcanics|Name source|City of Melbourne Bay, east coast of King Island, Grassy 1:25000 map sheet.|16-MAY-23
74595|City of Melbourne Volcanics|Unit history|City of Melbourne formation (Direen, 1999); Lower Tholeiite Sequence (Waldron & Brown, 1993).|16-MAY-23
74595|City of Melbourne Volcanics|Geomorphic expression|Low-lying dark outcrops, often with irregular flat tops.|16-MAY-23
74595|City of Melbourne Volcanics|Type section locality|Headland on south side of City of Melbourne Bay: 40.013S, 144.115 E.|16-MAY-23
74595|City of Melbourne Volcanics|Description at type locality|Peperites (basalt / shale) at base, overlain by agglomerates and volcaniclastic sandstones (30 m) then  roughly 60 m  of pillow basalts and flows; sequence dips moderately (50 degrees) SE.|16-MAY-23
74595|City of Melbourne Volcanics|Extent|Southeastern quadrant of King Island. This formation crops out in several fault bounded blocks both north and south of City of Melbourne Bay.|16-MAY-23
74595|City of Melbourne Volcanics|Thickness range|Approximately 90 m at type locality. May be locally thinner, e.g. 45 m near mouth of Conglomerate Creek.|16-MAY-23
74595|City of Melbourne Volcanics|Lithology|Tholeiitic basaltic andesite pillows, flows and sills; agglomerates; peperites; volcaniclastic sandstones; dolerites.|16-MAY-23
74595|City of Melbourne Volcanics|Depositional environment|Volcanically active basin; submarine volcanism.|16-MAY-23
74595|City of Melbourne Volcanics|Relationships and boundaries|Basal flows form peperites (i.e. are intermingled / interdigitated) with the underlying Yarra Creek Shale (Calver et al., 2004; Direen & Jago, 2008). Upper part of section is disconformably overlain by Shower Droplet Volcanics (Meffre et al., 2004).|16-MAY-23
74595|City of Melbourne Volcanics|Correlations|Probably broadly correlative with the Spinks Creek Volcanics of northwest Tasmania.|16-MAY-23
74595|City of Melbourne Volcanics|Proposed publication|Meffre, S., Direen, N.G., Crawford, A.J. and Kamenetsky, V., 2004. Mafic volcanics on King Island, Tasmania: evidence for break-up in east Gondwanaland at ca.579 Ma. Precambrian Research, 135, 177-191.|16-MAY-23
74595|City of Melbourne Volcanics|Comments|Medium-coarse grained basaltic andesite to dolerites and gabbros with interlocking ophitic to sub-ophitic textures. The basalts and basaltic andesites have moderate-low TiO2 contents (0.5¿0.7%), and unusual V-shaped chondrite normalised rare-earth element (REE) patterns. They show a tholeiitic fractional crystallisation trend characterised by strongly increasing Fe and Ti with increasing fractionation, consistent with crystallisation of olivine, plagioclase and chromite. They display mid ocean ridge basalt (MORB)-normalised multi-element patterns (Meffre et al., 2004).|16-MAY-23
74595|City of Melbourne Volcanics|References|Calver, C.R., Black, L.P., Everard, J.L. and Seymour, D.B., 2004. U-Pb zircon age constraints on late Neoproterozoic glaciation in Tasmania. Geology, 32(10): 892-896.Direen, N.G., 1999. Geology and geophysics of the Koonenberry Belt, far western New South Wales, and eastern Australian correlates. Pts 1 & 2. Ph.D Thesis, University of Tasmania, Hobart.Meffre, S., Direen, N.G., Crawford, A.J. and Kamenetsky, V., 2004. Mafic volcanics on King Island, Tasmania: evidence for break-up in east Gondwanaland at ca.579 Ma. Precambrian Research, 135, 177-191.Waldron, H.M. and Brown, A.V., 1993. Geological setting and petrochemistry of Eocambrian¿Cambrian volcano-sedimentary rock sequences from southeast King Island. Tasmanian Geological Survey Record, 1993/28: 28 pp.|16-MAY-23
74595|City of Melbourne Volcanics|Parent|Skipworth Subgroup, Grassy Group.|16-MAY-23
74595|City of Melbourne Volcanics|Proposer|N G Direen & C R Calver|16-MAY-23
4408|Comstock Formation|Name source|Initial Statement: This unit was defined in Corbett et al. (1974) as the Comstock Tuff, and was later referred to as the Comstock Formation (Corbett 1975, Corbett and Brown 1976), but was never registered at the Central Register of Australian Stratigraphic Names.  The aim of this application is to formally register this unit as the 'Comstock Formation' in order to allocate formal member names to two sub-units defined within the formation. The details given here are reasonably consistent with details given by Corbett et al. (1974) for the Comstock Tuff. However, more updated descriptions and other detailed information is also given. The Comstock Formation is the lowermost of two formations which make up the Tyndall Group. A full description of the Tyndall Group stratigraphy is given in White and McPhie (in prep).  Lyell Comstock Creek (geogrpahical location) AMG Grid Reference 5345500N - 38400E Gormanston sheet, Tasmanian Lands Department. Also Lyell Comstock Mine (often referred to as Comstock Mine) AMG Grid Reference 5344100N - 382100E.|16-MAY-23
4408|Comstock Formation|Unit history|Comstock Tuff of Corbett et al. (1974).|16-MAY-23
4408|Comstock Formation|Type section locality|The Comstock Formation was defined as the Comstock Tuff in the Comstock/Zig Zag Hill area by Corbett et al. (1974). A type section was given in Corbett et al. (1974) and is situated on Zig Zag Hill between 82535, 36115 (base) and 82535, 36175 (top; Lyell 1:63 360 sheet). The top of the Comstock Tuff as defined by Corbett et al. (1974), occurs at the base of a unit of laminated pink siltstone on Zig Zag Hill. However, more Comstock-type sandstone and breccia is exposed above this siltstone unit (as noted by Corbett et al. 1974) and therefore the top of the unit is more likely to be approximately 100-130 metres stratigraphically higher, at the top of the welded ignimbrite unit. The Zig Zag Hill Formation (new term) (referred to as the Jukes Formation by Corbett et al. 1974) sharply overlies the welded ignimbrite unit on Zig Zag Hill and contains deposits that have a different origin to deposits in the underlying Comstock Formation (as explained in White and McPhie in prep). The Comstock Formation is dominated by syn-eruptive crystal-rich volcaniclastic deposits and is clearly different to the overlying Jukes Formation dominated by post-eruptive polymict volcaniclastic conglomerate and sandstone.  I suggest that a type area be assigned to the Comstock Formation (i.e. the Comstock/Zig Zag Hill area) as the old type section on Zig Zag Hill is largely overgrown with vegetation and better exposures are seen 1 km to the southeast in the Comstock area and in the Comstock drill holes (e.g. C50: 477-1003 feet, C61: 222-407 m). On Zig Zag Hill, the Comstock Formation dips steeply to the northeast and is exposed between 5345800N - 381750E (base) and 5346200N - 382400E (top) (AMG Grid co-ordinates, Gormanston sheet, Tasmania 1:25 000 series, Tasmanian Lands Department)|16-MAY-23
4408|Comstock Formation|Extent|The Comstock Formation is exposed in the central part of the Mount Read Volcanics from the Lynchford area to the Mount Lyell district, and further north in the Anthony Road/Henty Canal and Moxon Saddle areas. Correlates of the Comstock Formation occur in the Mount Cripps Subgroup (Corbett 1992) in the Cradle Mountain Link Road area. Other correlates occur in the Winterbrook area (Pemberton and Vicary 1989) and possibly in parts of the Western Volcanosedimentary sequences (e.g. Pinnacles area, McKibben 1993). Correlates may also occur further south in the Jukes-Darwin area (Corbett 1992).  However, some of these units are more recently interpreted as part of the Eastern quartz-phyric sequence (Corbett et al. 1993).|16-MAY-23
4408|Comstock Formation|Thickness range|The Comstock Formation varies in thickness from approximately 200 m (Comstock area) to 800 m thick (Henty Canal, Cradle Mountain Link Road areas). Thinner, incomplete sequences are also exposed in parts of the Mount Read Volcanics (e.g. near the Mount Lyell Mill).|16-MAY-23
4408|Comstock Formation|Lithology|The Comstock Formation is dominated by massive crystal-rich volcaniclastic sandstone and massive to normally graded crystal-, lithic-rich volcaniclastic lithic breccia units. Minor facies include laminated and graded fine sandstone/mudstone units, carbonate (fossiliferous in places; Jago et al. 1972), welded ignimbrite, ignimbrite-clast volcaniclastic breccia, coherent rhyolite (flow banded in places) and rhyolite clast volcaniclastic breccia. The lower part is derived largely from andesitic to dacitic volcanism (Lynchford Member) while the upper part is derived largely from rhyolitic to dacitic volcanism (Mount Julia Member). Details are given in White and McPhie (in prep). Crystal-rich volcaniclastic facies containing approximately 1-5% titanomagnetite, dominate in this formation which gives it a characteristically high magnetic signature relative to the surrounding units. Corbett et al. (1974) defines the Comstock Tuff as comprising an interbedded sequence of quartz-keratophyric tuff, breccia, sandstone, shale and limestone.|16-MAY-23
4408|Comstock Formation|Relationships and boundaries|The character of the lower contact (to older underlying rocks) appears to be conformable in some areas (e.g. Comstock, Anthony Road) where an interfingering contact to the underlying andesite units is observed. In some areas (e.g. Lynchford, Moxon Saddle) the Comstock Formation is interpreted to rest unconformably on, or in fault contact with older rocks of the Mount Read Volcanics. In other areas the contact is poorly defined due to poor exposure.  In areas of good exposure (e.g. Comstock, Anthony Road, Henty Canal), the upper contact of the Comstock Formation (with the overlying Zig Zag Hill Formation) is gradational and conformable.|16-MAY-23
4408|Comstock Formation|Age reasons|The age is best constrained by fossil dating. Marine fossils found in a brown mudstone unit (largely trilobites) within the 'Comstock Formation correlates' on the Cradle Mountain Link Road are dated as late Middle Cambrian in age (Lejopyge laevigata II and III to Damesella torosa-Ascionepea janitrix zones) (Pemberton et al. 1991). The age range of these fossils is approximately 530 to 520 Ma (Shergold 1989). The fossiliferous carbonate (limestone) unit in the Comstock Formation at Comstock contains fauna of a similar age (late Middle to early Late Cambrian age: Jago et al. 1972). Recent isotopic U-Pb dating of magmatic zircons from 2 crystal-rich volcaniclastic sandstone samples in the Comstock Formation yielded two relatively young dates of 494.4+/-3.8 Ma and 502.5+/-3.3 Ma (Perkins and Walshe 1993).|16-MAY-23
37828|Corn Hill Formation|Name source|Named from a nearby property "Corn Hill" over-which it is the dominant bed-rock.|16-MAY-23
37828|Corn Hill Formation|Unit history|Corn Hills beds (Hills, 1982)|16-MAY-23
37828|Corn Hill Formation|Geomorphic expression|Ranging from steep but low relief at type section to undulating farm land.|16-MAY-23
37828|Corn Hill Formation|Type section locality|146degrees49'50" E 41degrees15'56" S Bulls Road (off Rookery Road) Northern Tasmania.The type locality is a substantial road cutting on the southern side of the road.  It is the most substantial outcrop of the unit known although good exposure is available in drill cores DDH B48 and DDH B49 drilled for the purpose of geotechnical investigation of the Mill Site for the Beaconsfield Gold Mine held at the Beaconsfield Gold Mine core shed.[Reference sections?]|16-MAY-23
37828|Corn Hill Formation|Description at type locality|The type locality is a substantial road cutting on the southern side of the road.  The site was that from which Banks and Rickards (1989) recovered graptolites and Hills (1982) recovered the remaining fauna and first described the unit.|16-MAY-23
37828|Corn Hill Formation|Extent|Flowery Gully - Leonardsburgh area, southwest of Beaconsfield, Northern Tasmania.|16-MAY-23
37828|Corn Hill Formation|Thickness range|Indeterminate due to poor outcrop, folding complexity truncation by faulting but of the order of 600m.|16-MAY-23
37828|Corn Hill Formation|Lithology|Foliated micaceous shaley quartz siltstone with lesser quartzwacke sandstone, siltstone and shale beds of turbiditic character.|16-MAY-23
37828|Corn Hill Formation|Depositional environment|Moderately deep water (probably outer shelf) turbidites.|16-MAY-23
37828|Corn Hill Formation|Fossils|Monograptus thomasi, Actinopteria meridionalis, Pracadium sp., Styliolina minuta and others of lesser significance.|16-MAY-23
37828|Corn Hill Formation|Relationships and boundaries|Unconformably overlies the (as yet formally undefined) Johnson Creek siltstone of Silurian age (correlated with the Eldon Gp of Western Tasmania) and truncated above by Tabberabberan age Cabbage Tree Thrust.  Neither boundary is observable at the type locality.  The position of the lower boundary can be approximated due to the contrasting competency of the shaley Corn Hill Formation with respect to the more massive quartz sandstone at the top of the Johnson Creek siltstone in poor outcrop east of the Flowery Gully Road 500m due west of the type locality.  The boundary is considered to be an unconformity due to the constraints of contrasting lithology and faunal control, the Johnson Creek siltstone being of Early Silurian age (Hills, 1982).  The upper boundary of the Corn Hill Formation is a thrust juxtaposing it beneath a conformable sedimentary sequence of demonstrable Cambrian - Early Ordovician age (Jago, 1980; Laurie, 1996a; 1996b; 1998; Laurie and Hills, in prep.)  The position of the thrust is constrained within a few tens of metres along the western flank of the Cabbage Tree Hill - Salisbury Hill strike ridge immediately west of Beaconsfield and is constrained in drill core from the Beaconsfield Gold Mine (DDHs B13, B32 & B50) 7km NNW of the type locality where it occurs as a sheared pug and hydrothermal alteration zone over several metres thickness.  It is thought that the thrust represents a major fluid path for gold mineralisation.  The drill holes do not penetrate the thrust.  The thrust outcrops poorly as a zone of shearing and clay pug over a width of 1m in a road cutting 500m northeast of the type locality where Ordovician sediments overlie the Corn Hill Formation.|16-MAY-23
37828|Corn Hill Formation|Age reasons|Early Devonian (Pragian) based on fossils, particularly M. thomasi.|16-MAY-23
37828|Corn Hill Formation|Correlations|Mathinna Group (Hills, 1982; Elliot, Woodward & Gray, 1993), lithological, sedimentological and biostratigraphical; Sidling sandstone, Panama Group, Mathinna Supergroup (Reed, in prep), lithological, sedimentological and biostratigraphical; Wilson Creek Shale, Victoria (Banks and Rickards, 1989), biostratigraphical.|16-MAY-23
37828|Corn Hill Formation|Proposed publication|Rickards  et al. (in prep) Papers & Proceedings of the Royal Society of Tasmania|16-MAY-23
37828|Corn Hill Formation|Comments|The Corn Hill Formation is a typical turbidite deposit exhibiting characteristic alteration from shale to quartzwacke sandstone over intervals of approximately 1m.  Sedimentary structures such as slumping, flute casting, current bedding and small scale erosional cut-offs are common-place at the type locality and elsewhere.  The flute casting and current bedding in particular indicated deposition from the west-southwest.|16-MAY-23
37828|Corn Hill Formation|References|*BANKS, M.R., & Rickards, R.B., 1989.  Early Devonian graptolites from Tasmania.  Pap. Proc. R. Soc. Tasm.  123: 111-117.     *ELLIOT, C.G., Woodward, N.B. & Gray, D.R., 1993.  Complex regional fault history of the Badger Head region, northern Tasmania, Australian Journal of Earth Sciences, 40: 155-168.    *HILLS, P.B., 1982.  The geology of the Lower and Middle Palaeozoic rocks of Flowery Gully, Northern Tasmania, BSc Honours thesis (unpublished), University of Tasmania, Hobart    *HILLS, P.B., 1998.  Tasmania gold deposit, Beaconsfield, in Geology of Australian and Papua New Guinean Mineral Deposits (Eds. D.A. Berkman and D.H. MacKenzie), pp 467-472 (The Australasian Institute of Mining and Metallurgy: Melbourne). Jago, J.B., 1980.  Late Middle Cambrian fossils from Beaconsfield, Tasmania.  Pap. Proc. R. Soc. Tasm. 114: 219-223.  *LAURIE, J.R., 1996a.Macrofossils from the Cabbage Tree Formation, Middle Arm Gorge, near Beaconsfield, Tasmania, Australian Geological Survey Organisation Professional Opinion 1996/008 (unpublished).    *LAURIE, J.R., 1996b.  Macrofossils from the ?Cabbage Tree Formation, along Bull's Road, near Flowery Gully, Tasmania, Australian Geological Survey Organisation Professional Opinion 1996/009 (unpublished).    *LAURIE, J.R., 1998.  Macrofossils from SW of Bulls Road, Winkleigh and Pentlands Road, Northern Tasmania, Australian Geological Survey Organisation Professional Opinion 1998/06 (unpublished).     *LAURIE, J.R. & Hills, P.B., in prep.  Early Ordovician fossils from the Beaconsfield area, Northern Tasmania.  Pap. Proc. R. Soc. Tasm.    *MacDONALD, G., Hills, P.B. Reed, A.R., Zengerer, M., Morrison, K.C. and Roach, M., 2001.  Beaconsfield Region, in Structure and setting of Proterozoic and Palaeozoic rocks in the Tamar region, Northern Tasmania, (Ed. A. R. Reed), Geological Society of Australia Specialist Group in Tectonics and Structural Geology ; Field Guide No. 9.  Pp. 25-42.    *REED, A.R., In Prep.  Pre-Tabberabberan deformation in eastern Tasmania: a southern extension of the Benambran Orogeny.  A.J.E.S.     *RICKARDS, R.B., Hills, P.B., Banks, M.R. and MacDonald, G., In Prep. A new discovery of Monograptus thomasi (Early Devonian) southwest of Beaconsfield, Tasmania and its significance. Pap. Proc. R.Soc. Tasm.|16-MAY-23
24229|Cotcase Creek Formation|Name source|Cotcase Creek [DN540560], Wedge 1:000 000 Mapsheet.|16-MAY-23
24229|Cotcase Creek Formation|Type section locality|The outcrop area as indicated on the Pedder Mapsheet is the designated type area.|16-MAY-23
24229|Cotcase Creek Formation|Extent|Unit is exposed over about 70 km2 in the Weld Valley between Frodsham's Pass and the Snake River. On the Pedder 1:50 000 mapsheet rocks belonging to this unit are indicated or prefixed with the symbol Cewc.|16-MAY-23
24229|Cotcase Creek Formation|Thickness range|Of the order of 2 km; uncertain due to faulting and possible folding.|16-MAY-23
24229|Cotcase Creek Formation|Lithology|Dominantly ;massive, fine-grained pale grey dolomite; units of dolomitic mixtite, mudstone and sandstone, interlayered on scales of metres to hundreds of metres, are common.|16-MAY-23
24229|Cotcase Creek Formation|Relationships and boundaries|All known contacts with other Precambrian units are faults. The unit is included in the Weld River Group on the basis of proximity and overall lithologic similarity.|16-MAY-23
24229|Cotcase Creek Formation|Age reasons|Late Precambrian (as for Weld River Group)|16-MAY-23
4882|Crescent Spur Sandstone|Name source|Crescent Spur (~CQ650070), about 1 km south of the former township of Luina (Arthur River 1:100 000 topographic sheet (7915) and Luina 1:25 000 topographic and geological sheets (3640). (Crescent Spur originally included Godkin Ridge, in the type locality, but is now applied to the southwest extension of the ridge).|16-MAY-23
4882|Crescent Spur Sandstone|Unit history|Previous terms are the "Micaceous Sandstone Formation" (Glasson & Hopwood 1962; Cox & Glasson 1967), 'massive micaceous sandstone' (Mason 1965), the "Crescent Spur Mica Sandstone Formation" (Cox 1968; Cox & Glasson 1971),"mica sandstone unit" (Ransom & Hunt 1975) and "Crescent Spur mica sandstone" (Palmer 1976). Corresponds to the "tuffs" of Hughes (1953) and to part of the Luina Beds of Rubenach (1973).|16-MAY-23
4882|Crescent Spur Sandstone|Geomorphic expression|Tends to form high ground, particularly in contrast to the underlying Hall Formation.|16-MAY-23
4882|Crescent Spur Sandstone|Type section locality|The north flank of Godkin Ridge on the Corinna Road, between CQ667085 and CQ683080 (e.g. Everard 2003).|16-MAY-23
4882|Crescent Spur Sandstone|Extent|Crops out over ~4km2 on Godkin Ridge, Crescent Spur and in the Whyte River valley near the confluence of "Falls Creek" (CQ644055), with probable correlates in the headwaters of "Falls Creek" (~CQ652048-CQ672055) and west of the Whyte River valley (~CQ645080).|16-MAY-23
4882|Crescent Spur Sandstone|Thickness range|over 350m thick at the type locality.|16-MAY-23
4882|Crescent Spur Sandstone|Lithology|Grey, fine- to medium-grained turbiditic micaceous greywacke and interbedded siltstone and mudstone, with thick units of red-brown arglllite and minor grey banded chert, spilitic basalt and associated mafic tuff and volcaniclastic greywacke (Collins 1983).|16-MAY-23
4882|Crescent Spur Sandstone|Depositional environment|Probably deep water, but turbiditic character and the presence of quartz and metasedimentary detritus (grains of quartzite, schist, muscovite, minor biotite and rare garnet) suggests a depositional setting close to a continental slope.|16-MAY-23
4882|Crescent Spur Sandstone|Fossils|None known.|16-MAY-23
4882|Crescent Spur Sandstone|Diastems or hiatuses|Not known|16-MAY-23
4882|Crescent Spur Sandstone|Relationships and boundaries|Conformably overlies the Hall Formation to the east, and is faulted against the Whyte River Complex to the west.|16-MAY-23
4882|Crescent Spur Sandstone|Age reasons|Considered "Eocambrian(?)-Early Cambrian(?)" by Collins (1983); now considered probably Early Cambrian, possibly Late Neoproterozoic (see Luina Group).|16-MAY-23
4882|Crescent Spur Sandstone|Alteration and Mineralisation|In greywacke, obliteration of clastic texture by tourmaline (+- quartz, fluorite, chlorite, late carbonate, minor biotite and rare cassiterite) adjacent to veins, and replacement of muscovite and chlorite by biotite with increasing depth (Collins 1983).|16-MAY-23
4882|Crescent Spur Sandstone|Defn author|Definition card completed by J. L. Everard from definition of Collins (1983), p. 306-307.|16-MAY-23
4882|Crescent Spur Sandstone|Comments|Subconcordant and discordant bodies of dolerite/gabbro intrude the crescent Spur Sandstone at the type locality (Collins 1983).|16-MAY-23
4882|Crescent Spur Sandstone|References|COX R. 1968. The economic geology of the Cleveland and Magnet mines, Tasmania. Ph.D. thesis, University of Sydney.  **COX R. & Glasson 1967. The economic geology of the Cleveland mine. In: The geology of western Tasmania- a symposium. University of Tasmania Geology Department, Hobart, November 1967.  **COX R. & Glasson 1971. The geology and mineralisation of the Cleveland mine, Tasmania. Economic Geology 66: 861-878.  **COLLINS, P. L. F. 1983. Geology and mineralisation at the Cleveland mine, western Tasmania. Ph.D. thesis, University of Tasmania.  **EVERARD, J.L. (compiler). 2003. Digital Geological Atlas 1:25000 series, Sheet 3640. Luina. Mineral Resources Tasmania.  **GLASSON K.R. & HOPWOOD T. 1962. Geological report, Mt Cleveland mine, Waratah district, Tasmania. Unpublished report, Aberfoyle Tin Development Partnership.  **HUGHES T.D. 1953. The Mt Cleveland mine. Unpublished report, Department of Mines Tasmania 1953: 82-85.  **MASON A. A. C. 1965. Tin ore deposits of Mt Cleveland. In: Geology of Australian Ore Deposits, 2nd Edition. 8th Commonwealth Mining and Metallurgical Congress, Melbourne: 503-505.  **PALMER K. G. 1976. The Cleveland tin deposit. In: Solomon M. & Green G.R. (Eds.) Ore deposits of western Tasmania. Excursion Guide 31Ac, 25th International Geological Congress, Sydney, 1976.  **RANSOM D. M. & HUNT F. L. 1975. The Cleveland tin mine. In Knights C. L. (Ed.) Economic geology of Australia and Papua- New Guinea. Australasian Institute of Mining and metallurgy Mon. 5: 584-591.  **RUBENACH M. J. 1973. The Tasmanian ultramafic-gabbro and ophiolite complexes. PhD thesis, University of Tasmania.|16-MAY-23
74645|Cumberland Creek Dolostone|Name source|Cumberland Creek, east Coast King Island, where the most complete section of this unit crops out. Grassy 1:25000 map sheet.|16-MAY-23
74645|Cumberland Creek Dolostone|Unit history|"Yarra Dolomite member" of Direen (1999).|16-MAY-23
74645|Cumberland Creek Dolostone|Geomorphic expression|Forms good, low buff to tan coloured outcrops on the rocky foreshore, and some low lying rock platforms.|16-MAY-23
74645|Cumberland Creek Dolostone|Type section locality|Cumberland Creek   -39.973S 144.109E|16-MAY-23
74645|Cumberland Creek Dolostone|Description at type locality|The formation in Cumberland Creek consists of ca. 9m thickness of east-facing and moderately east dipping (ca. 50 degrees) beds. The rocks are laminated dolostone passing up intothinly interbedded dolostone and shale, then shale with thin, pale grey, fine-grained limestone beds. Thin beds of dolostone and limestone within shale have sharp, slightly undulose tops suggestive of small-scale erosional relief.|16-MAY-23
74645|Cumberland Creek Dolostone|Extent|Southeastern quadrant of King Island. Best exposures are in fault-bound blocks within and south of Cumberland Creek to the southern side of City of Melbourne Bay  Metasomatised equivalent of this formation is known from the Grassy Mine in the SE corner of King Is.|16-MAY-23
74645|Cumberland Creek Dolostone|Thickness range|6-<10m.|16-MAY-23
74645|Cumberland Creek Dolostone|Lithology|Dolostone; shale; limestone(micrite).|16-MAY-23
74645|Cumberland Creek Dolostone|Depositional environment|Shallow water above storm wave base, based on presence of interpreted hummocky-cross stratification, wave ripples and planar cross beds.|16-MAY-23
74645|Cumberland Creek Dolostone|Relationships and boundaries|Conformably overlies the Cottons Breccia (Jago, 1974; Direen & Jago, 2008). Passes up conformably into the Yarra Creek Shale (Calver et al., 2004; Direen & Jago, 2008). Intruded by Ediacaran (575 ±3 Ma) mafic-intermediate sills of the Grimes Intrusive Suite (Meffre et al., 2004), and correlates are intruded  / metasomatised by the Early Carboniferous (350.8±1.7 Ma) 'Grassy granite' near the Grassy Mine (Black et al., 2005).|16-MAY-23
74645|Cumberland Creek Dolostone|Age reasons|Ediacaran inferred age. Older than 575±3 Ma, the age of the Grimes Intrusive Suite sills that intrude it (Meffre et al., 2004, Calver et al., 2004). Younger than 760 ± 12 Ma rocks of the Wickham Granite (Turner et al., 1998; Berry et al., 2005). A basal Ediacaran age is suggested by lithostratigraphic and  chemostratigraphic correlation with South Australia (Calver & Walter, 2000; Calver et al., 2004).|16-MAY-23
74645|Cumberland Creek Dolostone|Correlations|Correlated with the Nuccaleena Formation of South Australia (Calver & Walter, 2000; Calver et al., 2004), although this correlation  is considered problematic by Direen & Jago, (2008).|16-MAY-23
74645|Cumberland Creek Dolostone|Proposed publication|Meffre S, Direen N G, Crawford A J, & Kamenetsky V. 2004. Mafic volcanics on King Island, Tasmania: evidence for break-up in east Gondwanaland at ~579 Ma. Precambrian Research. 135, 177,191.|16-MAY-23
74645|Cumberland Creek Dolostone|Comments|The Cumberland Creek Dolostone was described also by Jago (1974) as 'Dolomite, dolomitic siltstone, siltstone and shale', and Calver & Walter (2000) as 'Dolostone', and Direen & Jago 2008, under its present name.Exposures at The Gut (-39.999S, 144.122E) display a variety of sedimentary structures indicative of shallow water deposition, including laminated cross-bedding and hummocky cross-stratification. In addition, Calver & Walter (2000) described intrastratal anticlines, which they interpreted to resemble (pseudo-)tepee structures. These features are also found in the (possibly equivalent) Nuccaleena Formation (SA), and  may be giant wave ripples (Allen & Hoffman, 2005).Based on its lithologic and  carbon and oxygen isotopic characteristics, Calver & Walter (2000) interpreted this unit as a 'cap carbonate' unit to a 'Snowball Earth' glacial deposit, represented by the underlying Cottons Breccia; this echoes a correlation made by Coats and Preiss (1987, p.106)  who suggested a possible correlation of the CCD with the Nuccaleena Formation.|16-MAY-23
74645|Cumberland Creek Dolostone|References|Allen, P.F. and Hoffman, P.F., 2005. Extreme winds and waves in the aftermath of a Neoproterozoic glaciation. Nature, 433: 123-127.Berry, R.F., Holm, O. and Steele, D.A., 2005. Chemical U-Th-Pb monazite dating and the Proterozoic history of King Island, southeast Australia. Australian Journal of Earth Sciences, 52: 461 - 471.Black, L.P., McClenaghan, M.P., Korsch, R.J., Everard, J.L. and Foudoulis, C., 2005. Significance of Devonian¿Carboniferous igneous activity in Tasmania as derived from U¿Pb SHRIMP dating of zircon. Australian Journal of Earth Sciences, 52: 807-829.Calver, C.R. and Walter, M.R., 2000. The late Neoproterozoic Grassy Group of King Island, Tasmania: correlation and palaeogeographic significance. Precambrian Research, 100, 299-312.Calver, C.R., Black, L.P., Everard, J.L. and Seymour, D.B., 2004. U-Pb zircon age constraints on late Neoproterozoic glaciation in Tasmania. Geology, 32(10): 892-896.Direen, N.G., 1999. Geology and geophysics of the Koonenberry Belt, far western New South Wales, and eastern Australian correlates. Pts 1 & 2. Ph.D Thesis, University of Tasmania, Hobart.Direen, N G, & Jago, J B, 2008, The Cottons Breccia (Ediacaran), and its tectonostratigraphic context within the Grassy Group, King Island, Australia: a rift-related gravity slump deposit. Precambrian Research 165: 1-14Meffre, S., Direen, N.G., Crawford, A.J. and Kamenetsky, V., 2004. Mafic volcanics on King Island, Tasmania: evidence for break-up in east Gondwanaland at ca.579 Ma. Precambrian Research, 135, 177-191.Turner, N.J., Black, L.P. and Kamperman, M., 1998. Dating of Neoproterozoic and Cambrian orogenies in Tasmania. Australian Journal of Earth Sciences, 45: 789-806.|16-MAY-23
74645|Cumberland Creek Dolostone|Parent|Grassy Group.|16-MAY-23
74645|Cumberland Creek Dolostone|Proposer|N G Direen & C R Calver.|16-MAY-23
5328|Deep Creek Volcanics|Name source|Deep Creek, the former name of Washington Creek, which enters the Whyte River 2 km south of Luina (CQ645061), Arthur River 1:100000 topographic sheet (7915), Luina 1:25000 topographic sheet (3640) and geological sheet (Everard 2003).|16-MAY-23
5328|Deep Creek Volcanics|Unit history|The term  "Deep Creek Basic Volcanics Formation" was used by Cox (1968) and Cox and Glasson (1971) for the mafic volcanic sequence cropping out southeast of the Cleveland Mine, and "Whyte Hill Basic Volcanics Formation" was applied by Cox (1968) for similar but less extensive mafic volcanics cropping out on Whyte Hill (CQ686078). Other terms used in the Cleveland Mine area have been the "lavas" (Hughes 1953), the "Basic Volcanics Formation" (Glasson and Hopwood 1962; Cox and Glasson 1967), the "massive volcanics" (Mason 1965), the "basic volcanic unit" (Ranson and Hunt 1975) and the "Deep Creek basic volcanics" (Palmer 1976); all coincide with and are superseded by Deep Creek Volcanics.|16-MAY-23
5328|Deep Creek Volcanics|Geomorphic expression|Tends to form high ground, particularly in contrast to the overlying Hall Formation.|16-MAY-23
5328|Deep Creek Volcanics|Type section locality|The type section is in Washington Creek (formerly Deep Creek) between CQ650065 and CQ665072. A reference section is also designated in "Falls Creek" (CQ646054 to CQ652047) and a short reference section occurs at the summit of Whyte Hill (CQ688079)(Collins 1983).|16-MAY-23
5328|Deep Creek Volcanics|Extent|Exposed for about 4 km2 in the Cleveland Mine area, between Washington Creek and "Falls Creek" and on Whyte Hill (Everard 2003). Elsewhere, the unit has not been fully differentiated from other constituent formations of the Luina Group.|16-MAY-23
5328|Deep Creek Volcanics|Thickness range|Probably over 600m southeast of the Cleveland Mine; the reference section in "Falls Creek" is 350m thick. However, the base is nowhere exposed and, on the other hand, any estimate may be exaggerated by faulting (Collins 1983).|16-MAY-23
5328|Deep Creek Volcanics|Lithology|Massive and locally pillowed spilitic basalt flow, with intercalated and interbedded fine-grained and lapilli tuff, volcaniclastic greywacke, red to chocolate-brown argillite and minor red-grey-green chert (Collins 1983).|16-MAY-23
5328|Deep Creek Volcanics|Depositional environment|Probably deep water, pelagic or continental slope.|16-MAY-23
5328|Deep Creek Volcanics|Fossils|None known|16-MAY-23
5328|Deep Creek Volcanics|Diastems or hiatuses|Not known|16-MAY-23
5328|Deep Creek Volcanics|Relationships and boundaries|Conformably overlain by the Hall Formation to the west. To the east, it is faulted against serpentinised mafic-ultramafic rocks at Whyte Hill. To the southeast (e.g. in "Falls Creek") it is bounded by a turbiditic greywacke sequence similar to the Crescent Spur Sandstone, but the nature of this boundary is unknown (Collins 1983).|16-MAY-23
5328|Deep Creek Volcanics|Structure and Metamorphism|Igneous clinopyroxene and calcic plagioclase are partly replaced by a greenschist facies including albite-oligoclase-actinolite, chlorite, titanite, epidote, calcite, magnetite, ilmenite (?) and sulphides (Collins 1983).|16-MAY-23
5328|Deep Creek Volcanics|Age reasons|Considered "Eocambrian(?)-Early Cambrian(?)" by Collins (1983); now considered probably Early Cambrian, possibly Late Neoproterozoic (see Luina Group).|16-MAY-23
5328|Deep Creek Volcanics|Correlations|Basalts in the Ramsay River and upper Arthur River/Wandle River areas may be correlates (Brown 1986; Williams & Brown 1983).  A suggested correlation with basalts intercalated with the Crimson Creek Formation (Collins 1983) is now considered unlikely (e.g. Brown and Jenner 1988; Brown 1989, p. 64).|16-MAY-23
5328|Deep Creek Volcanics|Alteration and Mineralisation|In the Cleveland Mine area, alteration of relict clinopyroxene to actinolite and albitised plagioclase to quartz, sericite, chlorite and minor biotite defines a halo adjacent to cassiterite-sulphide mineralisation. The halo is also defined by an increase in Rb, Sn and Zn and depletion of Na2O and K2O (Collins 1983).|16-MAY-23
5328|Deep Creek Volcanics|Geophysical Expression|Associated with moderate to strong anomalies on aeromagnetic images.|16-MAY-23
5328|Deep Creek Volcanics|Geochemistry|Basaltic (e.g. SiO2~ 46-50%, MgO~ 5-7%). Possibly three groups with ~1.6%, 2.5% and 3.7% TiO2 can be distinguished. Immobile element ratios (e.g. Nb/Y, Zr/P2O5) are characteristic of tholeiites. Weakly LEE-enriched((La/Yb)N 1.76-2.75) at 10-70 x chondrite (Collins 1983; Everard in Corbett et al. 2011).|16-MAY-23
5328|Deep Creek Volcanics|Defn author|Definition card completed by J. L. Everard from definition of Collins (1983), p. 303-305.|16-MAY-23
5328|Deep Creek Volcanics|References|BROWN  A. V. 1986. Geology of the Dundas¿Mt Lindsay¿Mt Youngbuck Region. Geological Survey Bulletin 62, Department of Mines Tasmania, Hobart.  **BROWN  A.V. 1989. Eocambrian-Middle Cambrian mafic volcanic rocks. In: BURRETT C. F. & MARTIN E. L. (eds). Geology and Mineral Resources of Tasmania. Geological Society of Australia Special Publication 15, 61-69.  **BROWN  A.V. & JENNER  G.A. 1988: Tectonic implications of the reinterpretation of Eocambrian-Cambrian mafic volcanics and associated ultramafic rocks in western Tasmania. In: TURNER N.J. (editor): The Geology and Evolution of the Latest Precambrian and Cambrian rocks in the Western Tasmania Terrane. Abstracts Volume, Geological Society of Australia (Tasmania Division).p. 23-25.  **CORBETT K.D. Quilty P. G. & Calver C. R. (Eds.) 2011. The Geological Evolution of Tasmania. Geological Society of Australia Special Publication.  **COX R. 1968. The economic geology of the Cleveland and Magnet mines, Tasmania. Ph.D. thesis, University of Sydney.  **COX R. & Glasson 1967. The economic geology of the Cleveland mine. In: The geology of western Tasmania- a symposium. University of Tasmania Geology Department, Hobart, November 1967.  **COX R. & Glasson 1971. The geology and mineralisation of the Cleveland mine, Tasmania. Economic Geology 66: 861-878.  **COLLINS, P. L. F. 1983. Geology and mineralisation at the Cleveland mine, western Tasmania. Ph.D. thesis, University of Tasmania.  **EVERARD, J.L. (compiler). 2003. Digital Geological Atlas 1:25000 series, Sheet 3640. Luina. Mineral Resources Tasmania.  **GLASSON K.R. & HOPWOOD T. 1962. Geological report, Mt Cleveland mine, Waratah district, Tasmania. Unpublished report, Aberfoyle Tin Development Partnership.  **HUGHES T.D. 1953. The Mt Cleveland mine. Unpublished report, Department of Mines Tasmania 1953: 82-85.  **MASON A. A. C. 1965. Tin ore deposits of Mt Cleveland. In: Geology of Australian Ore Deposits, 2nd Edition. 8th Commonwealth Mining and Metallurgical Congress, Melbourne: 503-505.  **PALMER K. G. 1976. The Cleveland tin deposit. In: Solomon M. & Green G.R. (Eds.) Ore deposits of western Tasmania. Excursion Guide 31Ac, 25th International Geological Congress, Sydney, 1976.  **RANSOM D. M. & HUNT F. L. 1975. The Cleveland tin mine. In Knights C. L. (Ed.) Economic geology of Australia and Papua- New Guinea. Australasian Institute of Mining and metallurgy Mon. 5: 584-591.  **WILLIAMS P.R. & BROWN A.V. 1983. An unusual occurrence of ultramafic and mafic rocks north of Mt Bischoff, NW Tasmania. Papers and Proceedings of the Royal Society of Tasmania 117, 53-58.|16-MAY-23
24243|Devils Eye Dolomite|Name source|Devils Eye Cave, at DN556472, Wedge 1:100 000 Mapsheet.|16-MAY-23
24243|Devils Eye Dolomite|Type section locality|Outcrop on Mt Anne's northeast ridge [DN550468-DN558480] and in the upper reaches of the Weld River [DN559544-DN554579] is designated the (composite) type area.|16-MAY-23
24243|Devils Eye Dolomite|Extent|The unit is exposed over a total of approximately 20 km2 on Mt Anne's northeast ridge; in the headwaters of Sandfly Ck. and along the upper reaches of the Weld River. The unit is indicated on the Pedder 1:50 000 Mapsheet with the symbol Cewtg.|16-MAY-23
24243|Devils Eye Dolomite|Thickness range|Very approximately 2 km; uncertain due to faulting.|16-MAY-23
24243|Devils Eye Dolomite|Lithology|Pale grey dolomite, typically of interbedded grainstone and fine-grained types.|16-MAY-23
24243|Devils Eye Dolomite|Relationships and boundaries|Conformably overlies Gomorrah Dolomite, and is conformably overlain by Styx Dolomite at DN554579.|16-MAY-23
24243|Devils Eye Dolomite|Age reasons|Late Precambrian (as/or Weld River Group).|16-MAY-23
24243|Devils Eye Dolomite|Proposed publication|Pap. Proc. R. Soc. Tasm., 123|16-MAY-23
74061|Fraser Formation|Name source|Fraser Beach and Fraser Bluff, off Naracoopa.|16-MAY-23
74061|Fraser Formation|Geomorphic expression|Weathers in preference to overlying Grassy Group, therefore leaving recessive  / poorly expressed landforms.|16-MAY-23
74061|Fraser Formation|Type section locality|-39deg55min21.228sec  = -39.92256333 : 144deg7min42.362sec = 144.1284339. Foreshore at Fraser Beach to Fraser Bluff|16-MAY-23
74061|Fraser Formation|Description at type locality|The formation at Fraser Beach consists of at least 390 m thickness of east-facing and moderately east dipping (ca. 60 degrees) beds forming low relief shore platform   / foreshore exposures at Fraser Beach.  Some minor parasitic folds at meter scale produce west-facing and west-dipping beds. The rocks are buff to grey cross-bedded quartzites, grey interbedded laminar to finely bedded graded siltstones, shales and rare conglomerates.|16-MAY-23
74061|Fraser Formation|Extent|Southeastern quadrant of King Island. This formation is known from the Grassy Mine in the SE corner of King Is; small outcrops are also present in roadcuts on Pegarah Rd and Robbins Rd, central King Is., and at the type section on the foreshore at Fraser Beach, Naracoopa.|16-MAY-23
74061|Fraser Formation|Thickness range|Unknown. Minimum 390 m. Gentle folding and equivalent low metamorphic grade in all exposures suggests the enveloping surface is relatively flat, so the full section is unlikely to be exposed.|16-MAY-23
74061|Fraser Formation|Lithology|Quartzite, siltstone, shale, conglomerate.|16-MAY-23
74061|Fraser Formation|Depositional environment|Unknown. Possibly shallow water to tidal flat.|16-MAY-23
74061|Fraser Formation|Relationships and boundaries|Angular unconformity with overlying volcanics of the Grassy Group (Skipworth Subgroup, Shower Droplet Volcanics). Upper contact was mapped by Direen (1999). Lower contact not exposed.|16-MAY-23
74061|Fraser Formation|Age reasons|Ediacaran inferred age. Older than 587 Ma, the age of unconformably overlying volcanic rocks, based on Sm-Nd radiometric dating (Meffre et al., 2004). Inferred to be younger than 760 ± 12 Ma rocks of the Wickham Granite (Turner et al., 1998; Berry et al., 2005).|16-MAY-23
74061|Fraser Formation|Correlations|Tentatively correlated with the Rocky Cape Group of the northwest Tasmanian mainland (Calver & Walter, 2000).|16-MAY-23
74061|Fraser Formation|Comments|The unit has previously appeared on geological maps but with no name and was simply treated as undifferentiated Proterozoic rock.|16-MAY-23
74061|Fraser Formation|References|Berry, R.F., Holm, O. and Steele, D.A., 2005. Chemical U-Th-Pb monazite dating and the Proterozoic history of King Island, southeast Australia. Australian Journal of Earth Sciences, 52: 461 - 471.Calver, C.R. and Walter, M.R., 2000. The late Neoproterozoic Grassy Group of King Island, Tasmania: correlation and palaeogeographic significance. Precambrian Research, 100, 299-312.Cox, S.F., 1989. Cape Wickham. In: C.F. Burrett and E.L. Martin (Editors), Geology and Mineral Resources of Tasmania. Geological Society of Australia Special Publication 15, pp. 26¿27.Direen, N.G., 1999. Geology and geophysics of the Koonenberry Belt, far western New South Wales, and eastern Australian correlates. Pts 1 & 2. Ph.D Thesis, University of Tasmania, Hobart.Meffre, S., Direen, N.G., Crawford, A.J. and Kamenetsky, V., 2004. Mafic volcanics on King Island, Tasmania: evidence for break-up in east Gondwanaland at ca.579 Ma. Precambrian Research, 135, 177-191.Turner, N.J., Black, L.P. and Kamperman, M., 1998. Dating of Neoproterozoic and Cambrian orogenies in Tasmania. Australian Journal of Earth Sciences, 45: 789-806.Streit, J.E. and Cox, S.F., 1998. Fluid infiltration and volume change during mid-crustal mylonitization of Proterozoic granite, King Island, Tasmania. Journal of Metamorphic Geology, 16: 197-212.|16-MAY-23
29222|Gelignite Creek Member|Name source|Gelignite Creek, [DN492512], Wedge 1:100 000 Mapsheet.|16-MAY-23
29222|Gelignite Creek Member|Type section locality|The outcrop area as indicated on the Pedder mapsheet, is the designated type area.|16-MAY-23
29222|Gelignite Creek Member|Extent|The unit is exposed over about 1/2 km2 along the crest of a strike ridge extending west from the Scotts Peak Road [DN485495] almost to the Huon River [DN460495]. The unit is indicated on the Pedder 1:50 000 geological map by the symbol Psq.|16-MAY-23
29222|Gelignite Creek Member|Thickness range|Approximately 200 m.|16-MAY-23
29222|Gelignite Creek Member|Lithology|White to pink, medium- to coarse-grained quartzarenite and lesser quartzitic pebble-conglomerate.|16-MAY-23
29222|Gelignite Creek Member|Relationships and boundaries|Part of the Huon River Formation, Pandani Group. Conformably overlies weathered white siltstone (Huon River Formation) at DN485495; top of unit obscured by younger cover.|16-MAY-23
29222|Gelignite Creek Member|Age reasons|Late Precambrian (as for Pandani Group).|16-MAY-23
29222|Gelignite Creek Member|Proposed publication|Explanatory Report, Department of Mines, Tasmania, for Pedder 1:50 000 Mapsheet.|16-MAY-23
24293|Gomorrah Dolomite|Name source|Gomorrah, the large eastern spur [DN555465] of Mt Anne's north-east ridge, Wedge 1:100 000 Mapsheet.|16-MAY-23
24293|Gomorrah Dolomite|Type section locality|Outcrops of massive dolomite along the ridge between DN543463 and DN550468 constitute the type area.|16-MAY-23
24293|Gomorrah Dolomite|Extent|The unit is exposed over approx. 4 km2 on Mt Anne's northeast ridge. A correlate is exposed over a larger area in the Weld River-Styx River-South Styx River area..|16-MAY-23
24293|Gomorrah Dolomite|Thickness range|Approximately 800 m.|16-MAY-23
24293|Gomorrah Dolomite|Lithology|Pale grey dolomite, usually massive, rarely laminated. Rare mudstone, sandstone, chert|16-MAY-23
24293|Gomorrah Dolomite|Relationships and boundaries|Conformably overlies Annakananda Formation at DN543463; and is conformably overlain by Devils Eye Dolomite at DN550468 (contact not observed).|16-MAY-23
24293|Gomorrah Dolomite|Age reasons|Late Precambrian (as for Weld R. Group).|16-MAY-23
24293|Gomorrah Dolomite|Proposed publication|Pap. Proc. R. Soc. Tasm., 123|16-MAY-23
74915|Grahams Road Volcanics|Name source|Bold Head, Grassy 1:25000 map sheet, where these rocks crop out.|16-MAY-23
74915|Grahams Road Volcanics|Unit history|'Upper Tholeiite sequence' of Waldron & Brown, 1993, 'Bold Head formation' of Direen, 1999; 'Bold Head Volcanics' of Meffre et al. (2004).|16-MAY-23
74915|Grahams Road Volcanics|Constituents|No identified members.|16-MAY-23
74915|Grahams Road Volcanics|Geomorphic expression|Bluffy, rounded outcrops of dark colour.|16-MAY-23
74915|Grahams Road Volcanics|Type section locality|Well-exposed coastal section between Cottons Beach (40.030 S, 144.099 E) and Bold Point (40.044 S, 144.104 E).|16-MAY-23
74915|Grahams Road Volcanics|Description at type locality|Approximately 1200 m thickness of interlayered mafic volcanic rocks, dominated by tholeiitic basalt flows 2-5m thick, with vesicular tops and brecciated bases, interbedded pillow lavas, and thick (tens to hundreds meters) of reworked volcaniclastic sandstones and conglomerates. Clasts within these conglomerates are mostly derived from the tholeiitic basalts. However, clasts of felsic volcanic rocks with embayed quartz phenocrysts, and coarse grained felsic intrusive rocks, are also present. The felsic clasts are intensely altered to an assemblage of secondary epidote, prehnite and quartz. The base and top of the section, which dips about 45 degrees SE, are not exposed.|16-MAY-23
74915|Grahams Road Volcanics|Extent|Southeastern quadrant of King Island. This formation is well exposed on the coast around Bold Head and extends inland to the vicinity of Grahams Road (Meffre et al., 2004). Metamorphosed equivalents are exposed within the various Grassy mines (Brown, 1990).|16-MAY-23
74915|Grahams Road Volcanics|Thickness range|Unknown. Minimum 1200 m exposed at Bold Head, but aeromagnetic modelling indicates an estimated maximum thickness of between 8500 and 13000m (Direen, 1999; Meffre et al., 2004).|16-MAY-23
74915|Grahams Road Volcanics|Lithology|Basalt, dolerite, (volcaniclastic) sandstone, (volcaniclastic) conglomerate, andesite, rhyolite (the latter just as clasts (??)|16-MAY-23
74915|Grahams Road Volcanics|Depositional environment|Volcanically active basin; submarine volcanism.|16-MAY-23
74915|Grahams Road Volcanics|Relationships and boundaries|Tholeiitic basalts of the Grahams Road Volcanics occur in fault contact with the Shower Droplet Volcanics, but based on cross-cutting dyke relationships and interpretation of aeromagnetic data (Meffre et al., 2004, Direen, 1999), must overlie them.Along-strike correlates are intruded  / metasomatised  by the Early Carboniferous (350.8±1.7 Ma) 'Grassy granite' (Black et al., 2005) aka 'Bold Head adamellite' (Brown, 1990) near the Bold Head orebody.|16-MAY-23
74915|Grahams Road Volcanics|Age reasons|Ediacaran. 579+/-16 Ma, based on a 5 point Sm-Nd isochron that includes the Shower Droplet Volcanics (Meffre et al., 2004).|16-MAY-23
74915|Grahams Road Volcanics|Correlations|Tentatively correlated with Spinks Creek Volcanics of Everard et al (1996) on geochemical grounds: Direen (1999); Meffre et al. (2004).|16-MAY-23
74915|Grahams Road Volcanics|Proposed publication|Calver, C.R. , 2008 (Compiler). Digital Geological Atlas 1:25,000 series, Sheet 2456. Grassy. Mineral Resources Tasmania.|16-MAY-23
74915|Grahams Road Volcanics|Comments|The formal name 'Bold Head Volcanics' was applied to this unit by Meffre et al. (2004), and also used by Direen & Jago (2008), but it is preferable to use a new name (Grahams Road Volcanics) as the geographic descriptor 'Bold Head' has previously been applied to a small monzogranite stock a few km inland of Bold Head (e.g. Large, 1969, 1971; Kwak & Tan, 1981; Calver & Seymour, 1995; Wesolowski et al., 1985).|16-MAY-23
74915|Grahams Road Volcanics|References|Brown, S.G., 1990. King Island scheelite deposits. In: F.E. Hughes (Editor), Geology of the Mineral Deposits of Australia and Papua New Guinea. Australian Institute of Mining and Metallurgy Monograph 14, pp. 1175-1180. **Black, L.P., McClenaghan, M.P., Korsch, R.J., Everard, J.L. and Foudoulis, C., 2005. Significance of Devonian-Carboniferous igneous activity in Tasmania as derived from U-Pb SHRIMP dating of zircon. Australian Journal of Earth Sciences, 52: 807-829.**Calver ,C. R. & Seymour, D. B., 1995, Explanatory notes for the Time-Space Diagram and Stratotectonic Elements Map of Tasmania, Tasmanian Geological Survey Record 1995/01, 62 p.**Direen, N.G., 1999. Geology and geophysics of the Koonenberry Belt, far western New South Wales, and eastern Australian correlates. Pts 1 & 2. Ph.D Thesis, University of Tasmania, Hobart.**Direen, N.G. , Jago, J.B. 2008 The Cottons Breccia (Ediacaran) and its tectonostratigraphic context within the Grassy Group, King Island: a rift-related gravity slump deposit Precambrian Research 165(1) p1-14 **Everard, J.L., Seymour, D.B., Brown, A.V., and Calver, C.R., 1996, Trowutta, Tasmania: Mineral Resources Tasmania Geological Atlas, scale 1:50,000, sheet 27(7915N). **Kwak, T.A.P. and Tan, T.H., 1981. The geochemistry of zoning in skarn minerals at the King Island (Dolphin) Mine. Economic Geology, 76(2): 468-497. **Large, R.R., 1969, The Bold Head adamellite contact aureole. Unpublished B.Sc(Hons) thesis, University of Tasmania. Large, R.R. 1971 Metasomatism and scheelite mineralization at Bold Head, King Island. AusIMM. Proceedings 238 p31-45 **Meffre, S., Direen, N.G., Crawford, A.J. and Kamenetsky, V., 2004. Mafic volcanics on King Island, Tasmania: evidence for break-up in east Gondwanaland at ca.579 Ma. Precambrian Research, 135, 177-191. **Waldron, H.M. and Brown, A.V., 1993. Geological setting and petrochemistry of Eocambrian-Cambrian volcano-sedimentary rock sequences from southeast King Island. Tasmanian Geological Survey Record, 1993/28: 28 p. **Wesolowski, D., Cramer, J.J., & Ohmoto, H., 1985, Scheelite mineralisation in skarns adjacent to Devonian granitoids at King Island, Tasmania. In Taylor, R.P. & Strong, D.F., (eds): Recent advances in the Geology of Granite-Related Mineral Deposits.  Canadian Institute of Mining and Metallurgy p. 234 - 251.|16-MAY-23
74915|Grahams Road Volcanics|Parent|Skipworth Subgroup, Grassy Group.|16-MAY-23
74915|Grahams Road Volcanics|Proposer|N G Direen & C R Calver.|16-MAY-23
37343|Grimes Intrusive Suite|Name source|Grimes Creek, west of Shower Droplet rock, east coast King Island Grassy 1:25000 map sheet.|16-MAY-23
37343|Grimes Intrusive Suite|Geomorphic expression|Forms pale grey lenses / tabular bodies of recessively weathering material, often with preferentially etched chilled margins. Basal sections may show development of cumulate igneous textures through differential weathering of phenocrysts and groundmass.|16-MAY-23
37343|Grimes Intrusive Suite|Type section locality|A full section through a continuous thick sill is exposed both in Skipworths Creek, -40.001, 144.113E , and Conglomerate Creek -39.982S, 144.109E, both NW of City of Melbourne Bay.  A composite AREA is defined because the original definition was proposed at Skipworths Creek (Meffre et al., 2004, after Direen, 1999), but a geochronological date was determined on an equivalent section of the same sill in Conglomerate Creek (Calver et al., 2004).|16-MAY-23
37343|Grimes Intrusive Suite|Description at type locality|The suite in the type area consists of a single differentiated sill up to 150m in thickness, conformable with bedding, and with chilled upper & lower margins. This sill has a gabbroic (wehrlite: olivine + pyroxene) ultramafic base, grading through gabbro and dolerite to an andesitic composition at its top.|16-MAY-23
37343|Grimes Intrusive Suite|Extent|Southeastern quadrant of King Island. This Suite contains a series of unusual differentiated sills that are intruded between about a kilometre south of Fraser Beach, and City of Melbourne Bay.|16-MAY-23
37343|Grimes Intrusive Suite|Thickness range|Observed sills range in thickness from 10 to 150m.|16-MAY-23
37343|Grimes Intrusive Suite|Lithology|Wehrlite, gabbro, dolerite, diorite, andesite.|16-MAY-23
37343|Grimes Intrusive Suite|Depositional environment|Shallow (subvolcanic) intrusive.|16-MAY-23
37343|Grimes Intrusive Suite|Relationships and boundaries|Sills are concordant or gently discordant to bedding of the Grassy Group, intrude both the Fraser Formation (cutting across the main N-S folding /axial plane cleavage), and the Grassy Group at around the level of the Robbins Creek Formation, the Cottons Breccia, the Cumberland Creek Dolostone, and the middle to lower Yarra Creek Shale.The Grimes Intrusive Suite probably predates the City of Melbourne Volcanics, because these shallowly emplaced intrusions are not found at stratigraphic levels higher than the middle of the Yarra Creek Shale (Meffre et al., 2004).|16-MAY-23
37343|Grimes Intrusive Suite|Age reasons|Ediacaran age. The sill in the type area was dated by Calver et al. (2004) to be 575±3Ma (SHRIMP U-Pb on zircon).|16-MAY-23
37343|Grimes Intrusive Suite|Proposed publication|Meffre, S., Direen, N.G., Crawford, A.J. and Kamenetsky, V., 2004. Mafic volcanics on King Island, Tasmania: evidence for break-up in east Gondwanaland at ca.579 Ma. Precambrian Research, 135, 177-191.|16-MAY-23
37343|Grimes Intrusive Suite|Comments|The suite covers a range of compositions from 45%-65% SiO2 and has a composition reflecting marked crustal contamination of a mafic source (Meffre et al., 2004). Thicker sills have a basal, gabbroic-ultramafic cumulate zone (45%-49% SiO2) resulting from fractional crystallization following intrusion. Sills intruding the Yarra Creek Shale are amygdaloidal, with unusual gas bubble textures (Meffre et al., 2004) suggesting intrusion at shallow depth into partially consolidated sediment. The central parts of the sills are medium- to fine grained rocks with long, narrow plagioclase and pyroxene crystals, and should be termed dolerites, as originally mapped by Jago (1974). However, the upper part of the sills is gradational to andesitic or granodioritic (60-65% SiO2)  in composition and grainsize (Meffre et al., 2004; Direen, unpubl. data) meaning that any compositional name is likely to be misleading. We hence prefer the non-compositional name Grimes Intrusive Suite to cover all of the observed compositions, and the range of observed gradational compositions and textures is in itself a distinguishing feature of this unit.This unit may also include rocks described as 'syenite dykes' by Waldron & Brown (1993) and 'syenite' by Calver & Walter (2000), although analyses presented by Waldron & Brown (1993) indicate more felsic compositions, especially at the 'base' of their sampled 'dyke' (60.5% SiO2), than the ultramafic compositions described by Meffre et al., 2004 for bases of the Grimes Intrusive Suite sills. It may be that the Grimes Intrusive Suite contains more than one intrusive phase, or alternatively, that these 'dykes' are unrelated to the sills. Waldron & Brown (1993) interpreted the syenites to be related to crustal melting, in which case they should be assigned to a separate suite, as they would not be strictly cogenetic with the Grimes Intrusive Suite.Similarly, after initial mapping compositional data was used by Meffre et al. (2004) to show a possible genetic relationship between the Grimes Intrusive Suite, and the volcanics of the Skipworth Subgroup. However, because the sills show very distinctive field characteristics, and petrography, and are not observed to anywhere feed into any of the three volcanic units that comprise the Skipworth Subgroup, we define them as a separate suite.|16-MAY-23
37343|Grimes Intrusive Suite|References|Calver, C.R., Black, L.P., Everard, J.L. and Seymour, D.B., 2004. U-Pb zircon age constraints on late Neoproterozoic glaciation in Tasmania. Geology, 32(10): 892-896.Direen, N.G., 1999. Geology and geophysics of the Koonenberry Belt, far western New South Wales, and eastern Australian correlates. Pts 1 & 2. Ph.D Thesis, University of Tasmania, Hobart.Meffre, S., Direen, N.G., Crawford, A.J. and Kamenetsky, V., 2004. Mafic volcanics on King Island, Tasmania: evidence for break-up in east Gondwanaland at ca.579 Ma. Precambrian Research, 135, 177-191.Waldron, H.M. and Brown, A.V., 1993. Geological setting and petrochemistry of Eocambrian¿Cambrian volcano-sedimentary rock sequences from southeast King Island. Tasmanian Geological Survey Record, 1993/28: 28 pp.|16-MAY-23
37343|Grimes Intrusive Suite|Proposer|N G Direen & C R Calver.|16-MAY-23
75977|Guilfoyle Creek Basalt|Name source|Guilfoyle Creek, a small stream rising immediately west of the type area.|16-MAY-23
75977|Guilfoyle Creek Basalt|Unit history|replaces Miners Ridge Basalt (also basalt, basalts) (not valid names, since Miners Ridge Sandstone in the same area has priority).|16-MAY-23
75977|Guilfoyle Creek Basalt|Geomorphic expression|Subdued. Less resistant than the Miners Ridge Sandstone in the overlying Yolande River Sequence.|16-MAY-23
75977|Guilfoyle Creek Basalt|Type section locality|Western flank of Miners Ridge, about 4 km S of Queenstown, western Tasmania (~42 deg 07' 08" S, 145 deg 33' 20" E). Shown as the unit "ophitic textured tholeiitic basalt lava, breccia and tuff, with associated intrusives" by Corbett et al. (1989) and Green & Everard (2006).|16-MAY-23
75977|Guilfoyle Creek Basalt|Extent|Strike length near type locality ~ 1.5 km; not known elsewhere (but see correlation).|16-MAY-23
75977|Guilfoyle Creek Basalt|General description|The unit occupies the core of a steeply north-plunging anticline in the Cambrian Yolande River Sequence (part of the Mt Read Volcanics)  and is the stratigraphically lowest unit in the area.|16-MAY-23
75977|Guilfoyle Creek Basalt|Thickness range|Apparent thickness at type locality > 170m, base not exposed or known.|16-MAY-23
75977|Guilfoyle Creek Basalt|Lithology|Amygdaloidal basaltic to picritic lava, breccia and volcaniclastics (picrites known only from drill-hole).|16-MAY-23
75977|Guilfoyle Creek Basalt|Depositional environment|Erupted subaqueously; possibly pelagic.|16-MAY-23
75977|Guilfoyle Creek Basalt|Fossils|None known.|16-MAY-23
75977|Guilfoyle Creek Basalt|Diastems or hiatuses|Not known|16-MAY-23
75977|Guilfoyle Creek Basalt|Relationships and boundaries|Formerly considered the stratigraphically lowest unit of the overlying Yolande River Sequence, but probably older basement to the latter. Contacts with the Yolande River Sequence probably faulted. Possibly allochthonous and tectonically emplaced in the Early Cambrian, before deposition of the Yolande River Sequence.|16-MAY-23
75977|Guilfoyle Creek Basalt|Identifying features|Distinguished from mafic units in the Mt Read Volcanics (e.g. Lynch Creek Basalt) by geochemistry (see below) and ophitic microtexture.|16-MAY-23
75977|Guilfoyle Creek Basalt|Structure and Metamorphism|Greenschist facies metamorphism; some relict igneous clinopyroxene.|16-MAY-23
75977|Guilfoyle Creek Basalt|Age reasons|Probably Early Cambrian. Older than the Middle Cambrian Mt Read Volcanics; probably structurally emplaced in the late Early or early Middle Cambrian Tyennan Orogeny.|16-MAY-23
75977|Guilfoyle Creek Basalt|Correlations|Formerly correlated with basalts in Crimson Creek Formation (Crawford et al. 1992). Recent data suggests a lithogeochemical correlation with the Birchs Inlet Volcanics basalts in the Mainwaring Group, and basalts in the Luina Group (McClenaghan & Findlay 1993; Seymour & Calver 1995; Corbett 2002).|16-MAY-23
75977|Guilfoyle Creek Basalt|Alteration and Mineralisation|Abundant secondary calcite, as veinlets, stringers and dissemination. Minor pyrite; rare chalcocite reported.|16-MAY-23
75977|Guilfoyle Creek Basalt|Geophysical Expression|Magnetic susceptibility of main basalt ~ 0.3 x 10-3 SI; picrites up to 80 x 10-3 SI.|16-MAY-23
75977|Guilfoyle Creek Basalt|Geochemistry|Low-Ti, high Mg basalt to picrite (MgO 6 - 28%). Mostly low in TiO2 (0.4 - 0.5%), Zr (20 - 25 ppm) and other incompatible elements, with Ti/Zr ratios (~90 - 160) higher than arc-related basalts from the overlying Mt Read Volcanics. Flat to strongly LREE-depleted rare earth patterns.|16-MAY-23
75977|Guilfoyle Creek Basalt|References|CORBETT K.D. 1979. Stratigraphy, correlation and evolution of the Mt Read Volcanics in the Queenstown, Jukes-Darwin and Mt Segwick areas. Geological Survey Bulletin 58, Tasmania Department of Mines.   **CORBETT K.D. 2002. Western Tasmanian Regional Minerals Program. Mount Read Volcanics Compilation. Updating the geology of the Mount Read Volcanics belt. Tasmanian Geological Survey Record 2002/19.  **CORBETT K. D., CALVER C.R., EVERARD J.L. & SEYMOUR D.B. 1:25000 Geological Series, Queenstown. Tasmania Department of |Resources and Energy; Department of Mines.  **CRAWFORD A.J., CORBETT K.D. & EVERARD J.L. 1992. Geochemistry of the Cambrian volcanic-hosted massive-sulfide-rich Mount Read Volcanics, western Tasmania, and some tectonic implications. Economic Geology 87, 597-619.  **DOWER B. 1991.The geology, geochemistry and tectonic setting of the Miners Ridge basalt and Lynch Creek basalt in the Mt Read Volcanic belt, western Tasmania. B.Sc. Hons. thesis, University of Tasmania.   **GREEN D.C. & EVERARD J.L. (COMP.). 2006. Geological Atlas 1:25000 series, Sheet 3833. Owen. Mineral Resources Tasmania.  **MCCLENAGHAN M.P & FINDLAY R.H. 1993. Geological Survey Explanatory Report. Macquarie Harbour Sheet 64 (7913). Tasmania Development and Resources, Division of Mines.  **SEYMOUR D. B.  & CALVER C. R.  1995. Explanatory notes for the Time-Space Diagram and Stratotectonic Elements Map of Tasmania. Report Mineral Resources Tasmania 1995/01.|16-MAY-23
7994|Halls Formation|Name source|Hall's workings, the original main open cut and underground workings on Hall's lode, lens A of the Cleveland Mine, on the south east flank of Godkin Ridge, CQ652069).|16-MAY-23
7994|Halls Formation|Unit history|The term "Hall's Formation" was originally used by Cox (1968) and Cox and Glasson (1971) for a single repetitive unit up to 30m thick containing a single "lode bed". The equivalent terms "Lode Formation" (Glasson and Hopwood 1962; Cox and Glasson 1967) and "lode horizon" (Mason 1965) have also been used for this unit. Ransom (1972) and Ransom and Hunt (1975) re-interpreted the structure at the mine and defined a "lode-bearing unit" 50-100m thick, which was later designated as "Hall's formation" by Palmer (1976). The Halls Formation also coincides with the "slate" of Hughes (1953).|16-MAY-23
7994|Halls Formation|Constituents|Includes Henrys Volcanic Member.|16-MAY-23
7994|Halls Formation|Geomorphic expression|Subdued.|16-MAY-23
7994|Halls Formation|Type section locality|The type section is a subsurface section at the Cleveland Mine (CQ651067), exposed in underground workings (e.g. mine section N) and in diamond drill core that was retained at the mine. Representative samples are held by Mineral Resources Tasmania and the University of Tasmania. A reference section occurs on Whyte Hill on the Corinna Road between CQ683080 and CQ686080 (Collins 1983; see also Everard 2003).|16-MAY-23
7994|Halls Formation|Extent|Exposed for over 3 km2 on Whyte Hill, on the southeast flank of Crescent Spur and the east bank of the Whyte River south of Washington (formerly Deep) Creek; a fault-emplaced outlier occurs within the Deep Creek Volcanics east of the Cleveland Mine (Collins 1983). Outside the Cleveland Mine area, the unit has not been differentiated from other constituent formations of the Luina Group.|16-MAY-23
7994|Halls Formation|Thickness range|80-120m in the Cleveland mine area. 50-150m quoted by Collins (1983, p. 64).|16-MAY-23
7994|Halls Formation|Lithology|Light to dark grey and purple shale and fine-grained tuff, with limestone, grey-green-red chert, greywacke, basic tuff and basalt.|16-MAY-23
7994|Halls Formation|Depositional environment|Probably deep water, pelagic or continental slope.|16-MAY-23
7994|Halls Formation|Fossils|none known|16-MAY-23
7994|Halls Formation|Diastems or hiatuses|not known|16-MAY-23
7994|Halls Formation|Relationships and boundaries|Conformably overlies the Deep Creek Volcanics to the east and south-east, and is conformably overlain to the west by the Crescent Spur Sandstone.|16-MAY-23
7994|Halls Formation|Identifying features|Characterised by presence of limestone, which is not known in the underlying and overlying formations (Collins 1983, p. 64).|16-MAY-23
7994|Halls Formation|Age reasons|Considered 'Eocambrian(?)-Early Cambrian(?)' by Collins (1983); now considered probably Early Cambrian, possibly Late Neoproterozoic (see Luina Group).|16-MAY-23
7994|Halls Formation|Correlations|A suggested correlation with the Crimson Creek Formation (Collins 1983) is now considered unlikely (e.g. Brown and Jenner 1988; Brown 1989, p. 64)|16-MAY-23
7994|Halls Formation|Alteration and Mineralisation|At the Cleveland Mine, the unit contains eleven lenses of cassiterite-sulphide mineralisation, divided into two groups (footwall and hangingwall lodes) by a wedge of basalt, the Henrys Volcanic Member.|16-MAY-23
7994|Halls Formation|Geochemistry|Chemical analyses indicate that the limestone beds are composed mainly of calcite (40-80%) and quartz or chert (10-42%)with only minor Fe, Mg and Mn (Collins 1983, p. 67).|16-MAY-23
7994|Halls Formation|Defn author|Definition card completed by J. L. Everard  24-May-2011, from definition of Collins (1983), p. 305-306.|16-MAY-23
7994|Halls Formation|References|BROWN  A.V. 1989a. Eocambrian-Middle Cambrian mafic volcanic rocks. In: BURRETT C. F. & MARTIN E. L. (eds). Geology and Mineral Resources of Tasmania. Geological Society of Australia Special Publication 15, 61-69.  **BROWN  A.V. & JENNER  G.A. 1988: Tectonic implications of the reinterpretation of Eocambrian-Cambrian mafic volcanics and associated ultramafic rocks in western Tasmania. In: TURNER N.J. (editor): The Geology and Evolution of the Latest Precambrian and Cambrian rocks in the Western Tasmania Terrane. Abstracts Volume, Geological Society of Australia (Tasmania Division).p. 23-25.  **COX R. 1968. The economic geology of the Cleveland and Magnet mines, Tasmania. Ph.D. thesis, University of Sydney.  **COX R. & Glasson 1967. The economic geology of the Cleveland mine. In: The geology of western Tasmania- a symposium. University of Tasmania Geology Department, Hobart, November 1967.  **COX R. & Glasson 1971. The geology and mineralisation of the Cleveland mine, Tasmania. Economic Geology 66: 861-878.  **COLLINS, P. L. F. 1983. Geology and mineralisation at the Cleveland mine, western Tasmania. Ph.D. thesis, University of Tasmania.  **EVERARD, J.L. (compiler). 2003. Digital Geological Atlas 1:25000 series, Sheet 3640. Luina. Mineral Resources Tasmania.  **GLASSON K.R. & HOPWOOD T. 1962. Geological report, Mt Cleveland mine, Waratah district, Tasmania. Unpublished report, Aberfoyle Tin Development Partnership.  **HUGHES T.D. 1953. The Mt Cleveland mine. Unpublished report, Department of Mines Tasmania 1953: 82-85. **MASON A. A. C. 1965. Tin ore deposits of Mt Cleveland. In: Geology of Australian Ore Deposits, 2nd Edition. 8th Commonwealth Mining and Metallurgical Congress, Melbourne: 503-505. **PALMER K. G. 1976. The Cleveland tin deposit. In: Solomon M. & Green G.R. (Eds.) Ore deposits of western Tasmania. Excursion Guide 31Ac, 25th International Geological Congress, Sydney, 1976. **RANSOM D. M. 1972. Reinterpretation of the geology of the Cleveland cassiterite-sulphide deposit. In: The Palaeozoic geology, structure and mineralisation of western Tasmania- a symposium. Geological Society of Australia, Tasmanian Division, p. 3-4. **RANSOM D. M. & HUNT F. L. 1975. The Cleveland tin mine. In Knights C. L. (Ed.) Economic geology of Australia and Papua- New Guinea. Australasian Institute of Mining and metallurgy Mon. 5: 584-591.|16-MAY-23
24313|Huon River Formation|Name source|Huon River [DN470500], Wedge 1:100 000 Mapsheet.|16-MAY-23
24313|Huon River Formation|Type section locality|The outcrop area as indicated on the Pedder mapsheet, is the designated type area.|16-MAY-23
24313|Huon River Formation|Extent|The unit is exposed over ca. 30 km2 in the southeastern part of the Wedge 1:100 000 Mapsheet around the headwaters of the Huon River. The unit is indicated on the Pedder 1:50 000 geological map by the symbols Psm, Psr, Psq and Pse.|16-MAY-23
24313|Huon River Formation|Thickness range|Approximately 3 km; uncertain due to faulting.|16-MAY-23
24313|Huon River Formation|Lithology|Pelite (phyllite, slate or mudstone) with lesser, interlayered dolomite and minor quartzarenite.|16-MAY-23
24313|Huon River Formation|Relationships and boundaries|Belongs to Pandani Group. Probably conformably overlies Lot Formation (contact not exposed). Probably conformably overlain by Mt Bowes Formation (contact not exposed).|16-MAY-23
24313|Huon River Formation|Age reasons|Late Precambrian (as for Pandani Group).|16-MAY-23
24313|Huon River Formation|Proposed publication|Explanatory Report, Department of Mines, Tasmania; for Pedder 1:50 000 Mapsheet.|16-MAY-23
75366|Industry Road Member|Name source|Named after a section of Industry Road centre on about: GDA94 Zone 55, 503040 mE, 5446355 mN|16-MAY-23
75366|Industry Road Member|Unit history|None.|16-MAY-23
75366|Industry Road Member|Constituents|None.|16-MAY-23
75366|Industry Road Member|Geomorphic expression|Generally elevated ground, with a distinctive topographic pattern of parallel strike ridges.|16-MAY-23
75366|Industry Road Member|Type section locality|The unit is generally not well exposed. The best exposures may occur within the Australian Army Stony Head Artillery Range, but due to severe access restrictions this is not considered suitable as a type area. Intermittent representative exposures of the unit occur on Industry Road between 502525 mE, 5445380 mN and 503405 mE, 5447600 mN (GDA94 Zone 55), and this is nominated as the type area.|16-MAY-23
75366|Industry Road Member|Description at type locality|Interbedded phyllitic slate and foliated very fine-grained quartz-rich sandstone, with almost-recumbent large-scale D1 folds and associated intensely developed gently dipping axial plane penetrative cleavage. This new member represents a transition package between the underlying Stony Head Sandstone and the rest of the Turquoise Bluff Slate.|16-MAY-23
75366|Industry Road Member|Extent|Currently mapped geographic extent comprises a slightly discontinuous 1.7 km wide outcrop belt exending from near the township of Lulworth on the Bass Strait coast in the north, some 30 km in (folded) strike length to the southern end of the Den Ranges (GDA94 Zone 55, 508160 mE, 5439635 mN) in the south.|16-MAY-23
75366|Industry Road Member|General description|Parent unit: Turquoise Bluff Slate (of the Tippogoree Group, of the Mathinna Supergroup).|16-MAY-23
75366|Industry Road Member|Thickness range|Estimated from structural profile sections, about 1200-1300 m. Mapping to date suggests the unit is relatively constant in thickness.|16-MAY-23
75366|Industry Road Member|Lithology|The slate component is similar to the lithology which dominates the rest of the Turquoise Bluff Slate. It is typically dark grey and indistinctly bedded internally, probably partly due to the high strain associated with the intense penetrative cleavage, which commonly shows a phyllitic sheen on the foliation surfaces. The other component interbedded with the slate typically comprises quartzose siltstone to fine-grained quartz-rich sandstone with a somewhat less intense penetrative cleavage typically at a low angle to bedding. Sedimentary structures indicating facing are typically scant, perhaps partly due to the high strain state.|16-MAY-23
75366|Industry Road Member|Depositional environment|Deep marine, distal turbidite to possibly marginal submarine fan.|16-MAY-23
75366|Industry Road Member|Fossils|None known.|16-MAY-23
75366|Industry Road Member|Diastems or hiatuses|None known.|16-MAY-23
75366|Industry Road Member|Relationships and boundaries|Contact sections are not particularly well exposed, but it is likely that this unit has conformable and transitional contacts with both the underlying Stony Head Sandstone, and the overlying main body of the parent Turquoise Bluff Slate.|16-MAY-23
75366|Industry Road Member|Identifying features|Mainly the geomorphic expression: the mix of resistant quartz-rich lithologies and more easily weathered pelitic slate give the unit a distinctive topographic pattern of parallel strike ridges which distinguish it from the underlying and overlying units, particularly visible in high-resolution DEM or LiDAR data and to a lesser extent in aerial photography.|16-MAY-23
75366|Industry Road Member|Structure and Metamorphism|Structural style is early large-scale almost-recumbent NE-vergent folds with gently dipping well developed to intense penetrative axial plane cleavage, overprinted by later, smaller-scale, steeply inclined SW-vergent open folds with axial plane crenulation cleavage selectively developed in the slaty lithologies. Metamorphism is anchizonal (200-300°C, sub-greenschist facies) according to Patison et al. (2001).|16-MAY-23
75366|Industry Road Member|Age reasons|Probably Early Ordovician. The youngest detrital zircons in the underlying Stony Head Sandstone are less than 500 Ma in age (Black et al., 2004). A graptolite of Early-Middle Ordovician age occurs in the main body of the Turquoise Bluff Slate a short interval above the top of the Industry Road Member (Banks & Smith, 1968).|16-MAY-23
75366|Industry Road Member|Correlations|No known correlates elsewhere within the outcrop area of the Mathinna Supergroup as at March 2010.|16-MAY-23
75366|Industry Road Member|Alteration and Mineralisation|The unit hosts about seven scattered historical small mines and prospects targeting gold-bearing quartz reef systems.|16-MAY-23
75366|Industry Road Member|Geophysical Expression|Nothing particularly distinctive, but a subdued striped dark-light pattern is evident on K-Th-U RGB images of airborne radiometric data, presumably due to the interlayered slate and quartz-rich lithologies in the unit.|16-MAY-23
75366|Industry Road Member|Geochemistry|No data.|16-MAY-23
75366|Industry Road Member|Defn author|David Seymour, Mineral Resources Tasmania, 7-SEP-2010|16-MAY-23
75366|Industry Road Member|Proposed publication|Seymour, D. B.; Woolward, I. R.; McClenaghan, M. P. 2010. Stratigraphic revision and re-mapping of the Mathinna Supergroup west of the Scottsdale Batholith, Northeast Tasmania (Explanatory Report for parts of 1:25 000 scale map sheets Low Head, Tam O'Shanter, Weymouth, Retreat, Lilydale, Bridport, Bowood, Nabowla, Lisle and Patersonia). Mineral Resources Tasmania, 1:25 000 Scale Digital Geological Map Series Explanatory Report 4.; possibly also AJES.|16-MAY-23
75366|Industry Road Member|References|Banks, M. R.; Smith, A. 1968. A graptolite from the Mathinna Beds, north eastern Tasmania. Australian Journal of Science, 31, 118-119. [RefID 20374]Black, L. P.; Calver, C. R.; Seymour, D. B.; Reed, A. 2004. SHRIMP U-Pb detrital zircon ages from Proterozoic and Early Palaeozoic sandstones and their bearing on the early geological evolution of Tasmania. Australian Journal of Earth Sciences, 51, 885-900. [RefID 60900]Patison, N. L.; Berry, R. F.; Davidson, G. J.; Taylor, B. P.; Bottrill, R. S.; Manzi, B.; Ryba, J.; Shepherd, R. E. 2001. Regional metamorphism of the Mathinna Group, northeast Tasmania. Australian Journal of Earth Sciences, 48, 281-292. [RefID 23167]|16-MAY-23
24350|Lake Judd Formation|Name source|Lake Judd [DN530410], Wedge 1:100 000 Mapsheet.|16-MAY-23
24350|Lake Judd Formation|Type section locality|The outcrop area between DN498416 and DN508425 is the designated type area.|16-MAY-23
24350|Lake Judd Formation|Extent|The unit is exposed over a total of approximately 5 km2 in the Celtic Hill-Lake Judd area in the southeastern part of the Wedge 1:100 000 Mapsheet.|16-MAY-23
24350|Lake Judd Formation|Thickness range|Approximately 1 km|16-MAY-23
24350|Lake Judd Formation|Lithology|Phyllite and slate with abundant thin beds and laminae of quartz siltstone.|16-MAY-23
24350|Lake Judd Formation|Relationships and boundaries|Unit belongs to Mt Anne Group. Unit youngs northwards, away from unexposed contact (faulted?) with probably-older Twin Creeks Formation. Unit is conformably overlain by Sarah-Jane Quartzite at DN508425.|16-MAY-23
24350|Lake Judd Formation|Age reasons|Late Precambrian, due to tectonometamorphic grade and regional geological setting (see Turner, 1989).|16-MAY-23
24351|Lake Timk Formation|Name source|Lake Timk [DN560455], Wedge 1:100 000 Mapsheet.|16-MAY-23
24351|Lake Timk Formation|Type section locality|The outcrop area as indicated on the Pedder mapsheet, is the designated type area.|16-MAY-23
24351|Lake Timk Formation|Extent|Unit is exposed over approximately 0.5 km2 immediately south of Lake Timk.  The unit is indicated on the Pedder 1:50 000 Mapsheet by the symbol Cewtc.|16-MAY-23
24351|Lake Timk Formation|Thickness range|Range 0-approximately 300 m; uncertain due to faulting.|16-MAY-23
24351|Lake Timk Formation|Lithology|Pebbly dolomitic mudstone and siltstone, usually laminated.|16-MAY-23
24351|Lake Timk Formation|Relationships and boundaries|Structurally overlies Annakananda Formation, underlies Gomorrah Dolomite; but contacts are not exposed and may be faults.|16-MAY-23
24351|Lake Timk Formation|Age reasons|Late Precambrian (as for Weld River Group).|16-MAY-23
24351|Lake Timk Formation|Proposed publication|Pap. Proc. Roy. Soc. Tasm., 123|16-MAY-23
75363|Lone Star Siltstone|Name source|Named from the 'Lone Star Ridge' (GDA94 Zone 55: 524512 mE,  5435393 mN) over which it is the dominant bedrock|16-MAY-23
75363|Lone Star Siltstone|Unit history|Along with the Retreat Formation and Yarrow Creek Mudstone, replaces the Bellingham Formation (Strat No. 1426, of the former Mathinna Group)|16-MAY-23
75363|Lone Star Siltstone|Constituents|None.|16-MAY-23
75363|Lone Star Siltstone|Geomorphic expression|Ranging from undulating to steep terrain. Elevated ground south of the Lisle granodiorite. Generally lower than surrounding units. The effects of subsequent events prevent the formation from being distinguished by geomorphology alone.|16-MAY-23
75363|Lone Star Siltstone|Type section locality|Exposure throughout the unit is variable, and extensive outcrops are rare. Exposure at the type locality is intermittent. The tightly folded section lies east of the Sideling Range, between points 528962 mE, 5423313 mN and 532302 mE, 5431363 mN (GDA94, zone 55), on the Tasman Highway, and includes south Targa Hill Rd and Myrtle Bank Road.  See 1:25,000 topographic map series, sheets 5242: PATERSONIA and 5243: LISLE, as well as Mineral Resources Tasmania digital geology equivalents.|16-MAY-23
75363|Lone Star Siltstone|Confidential_type_locality|No.|16-MAY-23
75363|Lone Star Siltstone|Description at type locality|The west of the traverse is dominated by a basal unit comprising cleaved, upright folded, variably bioturbated marine siltstone with significant shale and mudstone. Thin planar laminations are typical, but may be obscured by deformation, bioturbation or weathering. Units of massive, medium to thick bedded sandstone, rarely lenticular, become more common eastwards towards the overlying Sideling Sandstone. Thickness: As estimated from structural profiles: approximately 1 km in the type area. Estimation is poorly constrained however due to complex folding and probable interruption by faults.|16-MAY-23
75363|Lone Star Siltstone|Extent|The currently mapped geographic extent comprises a sinuous folded horizon from near Fordington on the Bass Strait Coast approximately 45 km SSE to the Mt. Barrow Falls State Reserve.|16-MAY-23
75363|Lone Star Siltstone|General description|The dominance of siltstone over sandstone, the presence of bioturbation, Ludlow graptolites and deep marine mudstone, and a distinctive yellow signature on ternary radiometric images may distinguish the Lone Star Siltstone from other formations in the Mathinna Supergroup.|16-MAY-23
75363|Lone Star Siltstone|General description|Parent unit: Panama Group (of the Mathinna Supergroup).|16-MAY-23
75363|Lone Star Siltstone|Thickness range|Cross sections and preliminary modelling indicate a typical total average thickness of up to 1.5 km. This varies considerably due to interruption by faulting throughout the formation, and the possibility of submarine fan complexes along the transitional contact of the overlying Sideling Sandstone. Estimations are hampered by extensive post-Devonian cover of the formation south of the Lone Star Siltstone.|16-MAY-23
75363|Lone Star Siltstone|Lithology|The thinly laminated siltstone is typically thin bedded and fine- to medium-grained, although may form slabby medium beds approaching and within hornfelsed zones. Fine-grained lithologies are micaceous, and although locally weakly deformed on long fold limbs, elsewhere they assume a slaty cleavage with a phyllitic sheen. Significant black shale is rare, typically pyritic and locally graptolite-bearing. Bioturbation, soft sediment deformation, rare isolated cross beds and mud drapes have been observed in the basal unit. The sandstone is mostly fine-grained with a significant groundmass. Sorting is typically poor. Sedimentary structures associated with sandstone deposition are uncommon but increase in frequency up sequence.|16-MAY-23
75363|Lone Star Siltstone|Depositional environment|Marine, based on presence of graptolites, bioturbation and local turbidites within a passive margin setting (see geochemistry). The basal siltstone and shale of the formation is distal, and forms a relatively passive environment between the sandy submarine fan complexes of the underlying Retreat Sandstone and the increasing sandy sheet flows to the east,  which lead up to further sandy submarine fan complexes of the overlying Sideling Sandstone.|16-MAY-23
75363|Lone Star Siltstone|Fossils|Identification of graptolites from five new localities are yet to be confirmed but initial observations indicate assemblages are probably Ludlow in age. The graptolites outcrop in dark pyritic shale and fine-grained siltstone around the top of the basal unit. Similar ages have been attributed to graptolites at Boags Ridge and at Golden Ridge in Mathinna Supergroup sediments in NE Tasmania. Within the type section, Graptolites are located at 530791 mE, 5426628 mN (GDA94, zone 55), on the Tasman Highway. Significant but variable trace fossils and bioturbation are present within the formation and are concentrated in fine-grained siltstone in the basal unit. Examples of burrows fecal pellets and bedding obscured by bioturbation may be found at 529095 mE, 5423824 mN (GDA94, zone 55), on the Tasman Highway. The as yet unconfirmed presence of Chondrites of the Nereites Ichnofacies indicates a deep marine environment for the lower part of the formation.|16-MAY-23
75363|Lone Star Siltstone|Diastems or hiatuses|None known|16-MAY-23
75363|Lone Star Siltstone|Relationships and boundaries|Map relationships and bedding measurements indicate a conformable transitional boundary with the overlying Sideling Sandstone. Away from the type area, the boundary is often poorly exposed. The boundary with the underlying Retreat Formation is typically exposed as a relatively abrupt transition over several metres, and is probably conformable, although the contrast of the unit descriptions allows the possibility of an unconformity.|16-MAY-23
75363|Lone Star Siltstone|Identifying features|The basal siltstone and its distinctive yellow signature on ternary radiometric images is readily distinguished from the underlying sandstone dominant Retreat Formation. The ratio of siltstone to sandstone decreases towards the top of the Lone Star Siltstone, and the transitional boundary with the overlying Sideling Sandstone is defined as the point where the sandstone dominates siltstone. Younger units overlying and intruding the formation lack the well defined penetrative slaty cleavage and fold style of the Lone Star Siltstone.|16-MAY-23
75363|Lone Star Siltstone|Structure and Metamorphism|Folds are classified as typically upright to steeply inclined, shallowly plunging and close. Fold closures are rarely observed, but stereonet evidence indicates they may be chevrons, particularly in areas with no sandstone. A well developed axial planar penetrative slaty cleavage predominates. Metamorphism is anchizonal (200 - 300 degrees C, sub-greenschist facies) according to Patison et al. (2001).|16-MAY-23
75363|Lone Star Siltstone|Age reasons|Late Silurian, based on presence of probable Ludlow graptolite fossils. The conformably overlying Sideling Sandstone contains Lower Devonian plant fossils. The formation is intruded by the Scottsdale Batholith and the Lisle Granodiorite, both of which are probably Middle Devonian.|16-MAY-23
75363|Lone Star Siltstone|Correlations|Correlates possibly exist east of the Scottsdale Batholith, but none have been confirmed at this stage.|16-MAY-23
75363|Lone Star Siltstone|Alteration and Mineralisation|This formation hosts the Lisle-Golconda goldfields. Most of the goldfields are spatially closely related to small, geomorphically subdued, probably Middle Devonian granodiorite cupolas. 95% of gold in the goldfields was won from alluvial workings (Roach 1992). Devonian gold mineralisation in the Denison Goldfield is located at the contact between this formation and the underlying Retreat Formation.|16-MAY-23
75363|Lone Star Siltstone|Geophysical Expression|Where exposure is more extensive towards the south the basal siltstone is distinguished by a high Potassium and Thorium signature on K-Th-U RGB images of airborne radiometric data. Expression is variable at intermediate intensity of all three channels where the proportion of sandstone increases towards the transitional boundary with the overlying Sideling sandstone. High frequency linear magnetic anomalies occur locally adjacent to metamorphic aureoles, and may indicate magnetic marker units within the beds (Roach 1994).|16-MAY-23
75363|Lone Star Siltstone|Geochemistry|Using the geochemical classification of Herron (1988), the siltstone can be classified as wacke or shale, and the sandstone as litharenite. The formation has a passive margin tectonic setting, based on the geochemical classifications of Roser and Korsch (1986), and Bhatia and Crook (1986). The Lone Star Siltstone falls dominantly in the field for rocks with a quartzose sedimentary provenance, using the geochemical classification of Roser and Korsch (1988).|16-MAY-23
75363|Lone Star Siltstone|Defn author|I.R. Woolward, Mineral Resources Tasmania, 2-JUN-2010.|16-MAY-23
75363|Lone Star Siltstone|Proposed publication|Seymour, D. B.; Woolward, I. R.; McClenaghan, M. P. 2010. Stratigraphic revision and re-mapping of the Mathinna Supergroup west of the Scottsdale Batholith, Northeast Tasmania (Explanatory Report for parts of 1:25 000 scale map sheets Low Head, Tam O'Shanter, Weymouth, Retreat, Lilydale, Bridport, Bowood, Nabowla, Lisle and Patersonia). Mineral Resources Tasmania, 1:25 000 Scale Digital Geological Map Series Explanatory Report 4.; possibly also AJES|16-MAY-23
75363|Lone Star Siltstone|References|Bhatia M. R., Crook, K. A. W., 1986: Trace element characteristics of greywackes and tectonic setting discrimination of sedimentary basins. Contributions to Mineral Petrology, 92: 181-193. [REFID 40311] **Herron M. M., 1988. Geochemical classification of terrigenous sands and shales from core or log data. Journal of Sedimentary Petrology, 58: 820-829. **Patison, N. L.; Berry, R. F.; Davidson, G. J.; Taylor, B. P.; Bottrill, R. S.; Manzi, B.; Ryba, J.; Shepherd, R. E. 2001. Regional metamorphism of the Mathinna Group, northeast Tasmania. Australian Journal of Earth Sciences 48: 281-292. [RefID 23167] **Roach M. J., 1992. Geology and geophysics of the Lisle-Golconda goldfield, northeast Tasmania. Bulletin of the Geological Survey of Tasmania, 70: 189-198. **Roser B. P. and Korsch R. J., 1986. Determination of tectonic setting of sandstone-mudstone suites using SiO2 content and K2O/Na2O ratio. Journal of Geology, 94: 635-650. **Roser B. P. and Korsch R. J., 1988. Provenance signatures of sandstone-mudstone suites determined using discriminant function analysis of major-element data. Chemical Geology, 67, 119-139.|16-MAY-23
26311|Lonely Tarns Formation|Name source|Lonely Tarns, between DN550417 and DN550440, Wedge 1:100 000 Mapsheet.|16-MAY-23
26311|Lonely Tarns Formation|Type section locality|Outcrop areas at DN548416-DN548417, DN552428-DN552429, DN565437-DN565439 are designated the (composite)type area.|16-MAY-23
26311|Lonely Tarns Formation|Extent|The unit is exposed over a total of approximately 1 km2 in five separate, small outcrop areas in the Celtic Hill [DN470470] - Mt Sarah-Jane [DN550410] - Whitewater Creek [DN565440] area, southeastern part of Wedge 1:100 000 Mapsheet.|16-MAY-23
26311|Lonely Tarns Formation|Thickness range|Approximately 200 m.|16-MAY-23
26311|Lonely Tarns Formation|Lithology|Slate and cleaved mudstone with thin beds and laminae of quartz siltstone.|16-MAY-23
26311|Lonely Tarns Formation|Relationships and boundaries|Youngest known unit of Mt Anne Group. Conformably overlies Sarah-Jane Quartzite at DN548416. Top of unit unknown: either faulted or obscured by younger cover.|16-MAY-23
26311|Lonely Tarns Formation|Age reasons|Late Precambrian, due to tectonometamorphic grade and regional geological setting - see Turner, 1989.|16-MAY-23
26311|Lonely Tarns Formation|Proposed publication|Explanatory Report, Department of Mines, Tasmania, for Pedder 1:50 000 Mapsheet|16-MAY-23
75978|Loorana Granite|Name source|Township of Loorana, about 10 km north of Currie, King Island|16-MAY-23
75978|Loorana Granite|Unit history|Previously considered part of the Cape Wickham Granite ( e.g. Berry et al. 2005).|16-MAY-23
75978|Loorana Granite|Geomorphic expression|Forms small coastal bluffs; crops out poorly inland.|16-MAY-23
75978|Loorana Granite|Type section locality|The west coast of King Island between a point 300m  E of Netherby Point (western contact)(39 deg 56' 37" S, 143 deg 50' 43" E), and the southern end of Sandfly Beach (eastern contact)(39 deg 58' 43" S, 143 deg 52' 58" E).|16-MAY-23
75978|Loorana Granite|Description at type locality|Grey, medium- to fine-grained, equigranular to very sparsely K-feldspar-porphyritic biotite monzogranite.|16-MAY-23
75978|Loorana Granite|Extent|The Loorana Granite forms a meridional tract at least 47 km long and up to 6 km wide, extending north of the type locality to Cooper Bluff and offshore to New Year Island. South of the type locality, it crops out on the coast between Cataraqui Point and a point ~1 km N of Seal Rocks.|16-MAY-23
75978|Loorana Granite|General description|Probably separated from the Cape Wickham Granite by a screen of Surprise Bay Formation, largely obscured by sand cover.|16-MAY-23
75978|Loorana Granite|Lithology|Aplite veins, pegmatite veins and mafic enclaves up to 1 m across are locally present. Transitional to mylonite near the western contact.|16-MAY-23
75978|Loorana Granite|Relationships and boundaries|At Sandfly Beach and Fitzmaurice Bay, the eastern contact is intrusive and subconcordant with bedding in the Surprise Bay Formation. Rafts of the latter occur within the granite, and granite dykes occur within the SBF. Near Netherby Point and at Cataraqui Point, the western contact is a major shear zone against probable correlatives of the Surprise Bay Formation.|16-MAY-23
75978|Loorana Granite|Identifying features|A grey equigranular to sparsely porphyritic granite; biotite variably altered to chlorite; hornblende absent.  Is less felsic (SiO2 66.7-68.9%; FeOt 3.2 - 4.6; MgO 1.3 - 2.0%) than the main phase of the Cape Wickham Granite (SiO2 71.1 - 73.9%, FeOt 0.7 - 2.3%, MgO 0.2 - 0.6%).|16-MAY-23
75978|Loorana Granite|Structure and Metamorphism|May be strongly jointed. Unfoliated, to intensely sheared near the western contact.|16-MAY-23
75978|Loorana Granite|Age reasons|748 +/-2 Ma (U-Pb SHRIMP on zircon); sample from Badger Box Creek in the type area (Black et al. 1997|16-MAY-23
75978|Loorana Granite|Correlations|Coeval with or slightly younger than the Cape Wickham Granite (U-Pb SHRIMP on zircon 762 +/- 14 Ma, Black et al. 1997 and 760 +/- 12 Ma, Turner et al. 1998).|16-MAY-23
75978|Loorana Granite|Alteration and Mineralisation|Biotite is partly altered to chlorite, and feldspar is commonly sericitised. There is no known associated mineralisation.|16-MAY-23
75978|Loorana Granite|Geophysical Expression|Low magnetic susceptibility (~0.18 x 10-3 SI). Subdued aeromagnetic response. Radiometrics moderate to high but often blocked by sand cover.|16-MAY-23
75978|Loorana Granite|Geochemistry|Fresh, unaltered samples of the main lithology are weakly peraluminous (ASI 1.02-1.13), unfractionated (e.g. Rb 115-285 ppm, Sr 100-165 ppm, Ba 430-590 ppm) and belong to the I-type, Sr depleted, Y-undepleted class of Australian Proterozoic granites (Wyborn et al. 1992; Budd et al. 2001).|16-MAY-23
75978|Loorana Granite|References|BERRY R. F., HOLM O. H. & STEELE D. A. 2005.  Chemical U-Th-Pb monazite dating and the Proterozoic history of King Island, southeast Australia.  Australian Journal of Earth Sciences 52, 461-471.   **BLACK L. P., SEYMOUR D. B., CORBETT K. D., COX S. E., STREIT J. E., BOTTRILL R. S., CALVER C. R., EVERARD J. L., GREEN G. R., MCCLENAGHAN M. P., PEMBERTON J., TAHERI J. & TURNER N. J. 1997. Dating Tasmania¿s oldest geological events. Australian Geological Survey Organisation Record 1997/15.  **BUDD A.R., WYBORN L.A.I. & BASTRAKOVA I.V. 2001. The metallogenic potential of Australian Proterozoic granites. Geoscience Australia Record 2001/12.  **STREIT J. E. & COX S. F. 1998. Fluid infiltration and volume change during mid-crustal mylonitisation of Proterozoic granite, King Island, Tasmania.  Journal of Metamorphic Geology 16, 197 ¿ 212  **TURNER N. J., BLACK L. P. & KAMPERMAN M. 1998. Dating of Neoproterozoic and Cambrian orogenies in Tasmania. Australian Journal of Earth Sciences 45, 789-806.  **WYBORN L.A. I., WYBORN D., WARREN R.G. & DRUMMOND B.J. 1992. Proterozoic granite types in Australia: implications for lower crust composition, structure and evolution. Transactions of the Royal Society ofEdinburgh, Earth Sciences 83, 201-209.|16-MAY-23
24363|Lot Formation|Name source|Lot, a peak situated at DN545442, Wedge 1:100 000 Mapsheet.|16-MAY-23
24363|Lot Formation|Type section locality|The presently known outcrop area, as indicated on the Pedder mapsheet, is the designated type area.|16-MAY-23
24363|Lot Formation|Extent|The unit is exposed over about 5 km2 in the large cirque north of Lot. The unit is indicated on the Pedder 1:50 000 geological map by the symbol 'Psd'.|16-MAY-23
24363|Lot Formation|Thickness range|Approximately 1 km.|16-MAY-23
24363|Lot Formation|Lithology|Dolomite with lesser, interbedded slate and phyllite.|16-MAY-23
24363|Lot Formation|Relationships and boundaries|The oldest unit belonging to Pandani Group. Oldest parts of unit are faulted against Mt Anne Group (Precambrian). Unit probably conformably overlain (contact not exposed) by lithologically similar Huon River Formation. Elsewhere, unconformably overlain by late Precambrian Weld River Group.|16-MAY-23
24363|Lot Formation|Age reasons|Late Precambrian|16-MAY-23
24363|Lot Formation|Proposed publication|Explanatory Report, Department of Mines, Tasmania, for Pedder 1:50 000 Mapsheet|16-MAY-23
24364|Lottah Granite|Name source|From the hamlet of Lottah, 20 km northeast of St Helens, at GR855361 (Blue Tier 1:50 000 Sheet).|16-MAY-23
24364|Lottah Granite|Unit history|Gee & Groves (1971), Groves (1972, 1977), and McClenaghan et al. (1982) included the Lottah Granite in a group of granite bodies of various types, interpreted to intrude the Poimena Granite and termed collectively the "Lottah Sheets".  Lottah Granite is essentially synonymous with "Lottah pluton" referred to by McClenaghan (1985) and the Lottah Alkali-Feldspar Granite referred to by McClenaghan (in press).|16-MAY-23
24364|Lottah Granite|Type section locality|On the northern side of the bridge over Tin Dish Creek on Lottah Road (GR840361; Blue Tier). Lithology here is leucocratic zinnwaldite-topaz alkali-feldspar granite, typical of most of the Lottah Granite.|16-MAY-23
24364|Lottah Granite|Description at type locality|Near a disused logging track 200 m south of Cotton Creek (GR13439; Ringarooma). Lithology is porphyritic muscovite-biotite alkali-feldspar granite, which occupies an elliptical area of about 6 km2 on the northern margin of the largest body.|16-MAY-23
24364|Lottah Granite|Extent|The Lottah Granite crops out in two main areas. The larger, about 23 km2, extends in an irregular, crudely boomerang shape from GR846397 (Blue Tier), near Mt Michael, northwestward to a line between 817446 (Ringarooma 1:50 000) and 790444 (near Cross Creek) and west-northwestward to 790410 (approx.). From 790444 it extends southwestward, and from 790410 west-southwestward, to 748406, 1.5 km northwest of Weldborough. Small (0.4 to 1.2 km2) apophyses are centred on GR792448, 814409, 826389 (all Ringarooma), 844421, and 843391 (Blue Tier); numerous small apophyses and dykes are exposed in the upper reaches of Cotton Creek between 824433 and 836433.  The smaller body (about 6 km2) extends from the Anchor mine (GR848353; Blue Tier) westward to 821359 (Ringarooma) and northwestward to 824386. Both main bodies enclose or partly enclose several roof pendants (up to 2 km2) and apophyses (up to 1 km2) of the host Poimena Granite, particularly in the Emu Hill-Masher Hill area (around GR800420).|16-MAY-23
24364|Lottah Granite|Lithology|The bulk of the Lottah Granite consists of even-grained (weakly porphyritic in few small areas), very leucocratic zinnwaldite-topaz alkali-feldspar granite (equigranular phase) with minor tourmaline, fluorite, apatite, cassiterite, amblygonite(?), and very rare monazite and zircon (and/or xenotime). Secondary muscovite and/or sericite and kaolinite are present in some areas. The 6 km2 elliptical body in the north consists of moderately to strongly porphyritic muscovite-biotite alkali-feldspar granite (porphyritic phase) with minor topaz, fluorite, apatite, zircon, monazite, and rare cassiterite. Secondary sericite, chlorite, and calcite are commonly present in small amounts.|16-MAY-23
24364|Lottah Granite|Relationships and boundaries|The Lottah Granite intrudes the surrounding and, in places, overlying, Poimena Granite. It is intruded by dykes of dolerite (Devonian) and basalt (Tertiary), and overlain by Recent alluvial deposits.|16-MAY-23
24364|Lottah Granite|Identifying features|The Lottah Granite is characterised by low relief, except in the north where it is incised by Cotton Creek and its tributaries, and moderate to poor outcrop. Outcrop is generally in the form of pavements; boulders and tors are rare.|16-MAY-23
24364|Lottah Granite|Age reasons|The emplacement age of the Lottah Granite has been determined by means of Rb-Sr isotopes to be about 370 Ma (mid-Devonian: Mackenzie et al., in press).|16-MAY-23
24364|Lottah Granite|Proposed publication|Geochimica et Cosmochimica Acta Introduction. The Lottah Granite as defined here is part of a group of granite bodies referred to collectively as the "Lottah Sheets" by Gee & Groves (1971), Groves (1972, 1977), and McClenaghan et al., (1982).  It is essentially the same as the bodies of alkali-feldspar granite referred to by McClenaghan (1985) as the "Lottah pluton". No name has been formally defined.|16-MAY-23
24364|Lottah Granite|Comments|Published as Lottah alkali feldspar granite in ref 85/24833|16-MAY-23
24364|Lottah Granite|Category|1|16-MAY-23
24364|Lottah Granite|Proposer|Mackenzie D.E.|16-MAY-23
75980|Luina Group|Name source|Township of Luina, now abandoned, near the type locality.|16-MAY-23
75980|Luina Group|Unit history|Encompasses informal term Luina Beds (also beds) of Rubenach (1973). Equivalent to "Cleveland-Waratah association" of Williams (in Burrett & Martin 1989, p. 482) and variants of later authors (...Association, ...association and correlates, Cleveland Waratah Complex). Prior to 1989 was usually correlated with the Crimson Creek Formation (e.g. Brown 1986).|16-MAY-23
75980|Luina Group|Constituents|Three conformable formations: Deep Creek Volcanics (bottom), Halls Formation and Crescent Spur Sandstone (top)(Collins 1983).|16-MAY-23
75980|Luina Group|Type section locality|The type section is composite and is as for the constituent formations: Washington Creek (formerly Deep Creek) between CQ650065 and CQ665072; subsurface in the Cleveland Mine; and the north flank of Godkin Ridge on the Corinna Road, between CQ667085 and CQ683080 (Collins 1983; Everard 2003).|16-MAY-23
75980|Luina Group|General description|Probably part of an allochthonous association that also includes the Heazlewood River and Mt Stewart Ultramafic Complexes and associated boninitic and low-titanium tholeiitic lavas.|16-MAY-23
75980|Luina Group|Thickness range|> 1050 m (Deep Creek Volcanics  > 600 m; Halls Formation ~ 100 m; Crescent Spur Sandstone >/= 350 m)(Collins 1983).|16-MAY-23
75980|Luina Group|Lithology|Deep Creek Volcanics: massive, locally pillowed, spilitic, tholeiitic basalt, with interbedded tuff, volcaniclastic wacke, mudstone and chert. Halls Formation: grey and purple shale and fine-grained tuff, with limestone, chert, greywacke and basalt.  Crescent Spur Sandstone: turbiditic micaceous quartzose lithicwacke and interbedded siltstone and mudstone, with lesser mudstone, chert, basalt and tuff.|16-MAY-23
75980|Luina Group|Depositional environment|Probably deep water, pelagic or continental slope; the Crescent Spur Sandstone may represent the influx of turbidity currents containing material of continental derivation.|16-MAY-23
75980|Luina Group|Fossils|None known|16-MAY-23
75980|Luina Group|Diastems or hiatuses|Not known|16-MAY-23
75980|Luina Group|Relationships and boundaries|Dips and faces northwest in the type area; the base (of Deep Creek Volcanics) is not exposed. Near Mt Bischoff, the Group contains large blocks of Oonah Formation near the faulted contact with that unit, suggesting the proximity of an unconformity (Williams in Seymour 1989). The top of the Crescent Spur Sandstone is faulted.|16-MAY-23
75980|Luina Group|Identifying features|Deep Creek Volcanics and Hall Formation: Intercalated mafic volcanics, volcaniclastics, maroon to purple mudstone and chert; Crescent Spur Sandstone: micaceous quarzose lithicwacke with grains of quartzite, schist, muscovite, minor biotite and rare garnet indicative of a metasedimentary provenance.|16-MAY-23
75980|Luina Group|Age reasons|Unfossiliferous; probably Early Cambrian. Intruded by feeder dykes for lavas, of which the Heazlewood River Ultramafic Complex represents cumulates.  A 513.6 +/- 5 Ma age (U-Pb SHRIMP on zircon, Black et al. 1997) from a tonalite from the Complex therefore places a minimum age constraint on the Luina Group. Contacts with older units are faulted and a Late Neoproterozoic age is possible.|16-MAY-23
75980|Luina Group|Correlations|Probable correlates are present south and east of the Meredith Granite, between Mt Ramsay and Colebrook Hill, and in the Coldstream River-Boco area. Both are meridional, fault-bounded tracts of interbedded turbiditic volcaniclastic lithicwacke, tholeiitic lava flows and laminated siltstone and mudstone. A possible correlate lies in the Little Henty River-Avebury area, west of Zeehan. In northwest Tasmania, the Barrington Chert and overlying Motton Spilite are together a probable correlate.|16-MAY-23
75980|Luina Group|Alteration and Mineralisation|In the type area, the Luina Group is affected by hydrothermal alteration related to Devonian granites. The Hall Formation hosts the Cleveland Sn-Cu orebodies.|16-MAY-23
75980|Luina Group|Geophysical Expression|Basaltic units (incl. the Deep Creek Volcanics) are associated with moderate to strong anomalies on aeromagnetic images.|16-MAY-23
75980|Luina Group|Geochemistry|Unaltered samples of the Deep Creek Volcanics are tholeiitic basalts transitional between E-MORB and rift tholeiites. Near the type area, three groups with ~1.6%, 2.5% and 3.7% TiO2 can be distinguished.|16-MAY-23
75980|Luina Group|References|BROWN  A. V. 1986. Geology of the Dundas-Mt Lindsay-Mt Youngbuck Region. Geological Survey Bulletin 62, Department of Mines Tasmania, Hobart.  **BLACK L.P., SEYMOUR D.B., CORBETT K.D., COX S.E., STREIT J.E., BOTTRILL R.S., CALVER C.R., EVERARD J.L., GREEN G.R., McCLENAGHAN M.P., PEMBERTON J., TAHERI J. & TURNER N.J. 1997. Dating Tasmania¿s oldest geological events. Australian Geological Survey Organisation Record 1997/15.  **COLLINS, P. L. F. 1983. Geology and mineralisation at the Cleveland mine, western Tasmania. Ph.D. thesis, University of Tasmania.  **EVERARD, J.L. (compiler). 2003. Digital Geological Atlas 1:25000 series, Sheet 3640. Luina. Mineral Resources Tasmania.  **RUBENACH M. J. 1973. The Tasmanian ultramafic-gabbro and ophiolite complexes. PhD thesis, University of Tasmania (unpubl.).  **SEYMOUR, D.B. (compiler). 1989. Geological Survey Explanatory Report Geological Atlas 1:50,000 series Sheet 36 (8015N) St Valentines.  **WILLIAMS E. 1989. Summary and synthesis. In: BURRETT C.F. AND MARTIN E.L. (eds) Geology and Mineral Resources of Tasmania. Geological Society of Australia Special Publication 15, 468-499.|16-MAY-23
29474|Lynchford Member|Name source|Initial Statement: The Lynchford Member is the lower member of two members in the Comstock Formation. The Comstock Formation is the lowermost of two formations in the Tyndall Group. The Lynchford Member correlates with the "Lynchford Tuff" defined by Corbett (1979). The unit is redefined herein and renamed the Lynchford Member. Lynchford (place name), 5 km southwest of Queenstown, western Tasmania (AMG Grid Reference 5336000N - 378000E Strahan sheet, Tasmania 1:25 000 series topographical map, Tasmanian Lands Department).|16-MAY-23
29474|Lynchford Member|Unit history|Lynchford Tuff, Corbett (1979).|16-MAY-23
29474|Lynchford Member|Type section locality|The type section is located in the Lynchford area, immediately east of the Queen River. The rocks dip steeply to the east and west, facing west, and are exposed along the Huxley Track between  5337500N - 379520E (base) and 5337800N - 378960E (top; Strahan sheet, Tasmania 1:25 000 series topographical map, Tasmanian Lands Department). A fault repetition exposes Lynchford Member facies further west along the Huxley Track. Corbett (1979) refers to this sequence of rocks as the Lynchford Tuff, and noted their similarity to the Comstock Tuff (Comstock Formation) deposits at Comstock. The Lynchford Member is approximately 600-700 m thick at the type section locality.|16-MAY-23
29474|Lynchford Member|Extent|The Lynchford Member is well exposed in the central part of the Mount Read Volcanics, just northeast of Lynchford. It is also exposed in the Zig Zag Hill, Comstock, Anthony Road and Henty Canal/Howards Road areas. Possible correlates of the Lynchford Member occur in the Mount Cripps Subgroup in the Cradle Mountain Link Road area and possibly in parts of the Western Volcanosedimentary sequences (e.g. Pinnacles area, McKibben 1993).|16-MAY-23
29474|Lynchford Member|Thickness range|The Lunchford Member varies in thickness from approximately 60 m (Comstock, Henty Canal area) to 600-700 m thick (Lynchford). The Tyndall Group sequence at Lunchford is composed entirely of quartz-poor crystal-rich volcaniclastic sandstone/breccia and laminated mudstone facies of the Lynchford Member (Lunchford Tuff, Corbett 1979). In the Anthony Road area, the Lynchford Member is approximately 200 m thick.|16-MAY-23
29474|Lynchford Member|Lithology|The Lynchford Member forms the lower part of the Comstock Formation and comprises four main facies: 1) quartz-poor crystal-rich volcaniclastic sandstone;  2) laminated fine sandstone/mudstone;  3) volcaniclastic lithic breccia;  4) carbonate. The quartz-poor crystal-rich volcaniclastic sandstone facies is the most common facies in the Lynchford Member and occurs in the Lynchford, Comstock, Zig Zag Hill, Anthony Road and Henty Canal areas. The crystal-rich sandstone is generally massive and contains lenses of laminated fine sandstone and mudstone, and volcaniclastic lithic breccia. The crystal-rich facies contains abundant crystals and crystal fragments (35-70%), comprising largely plagioclase and  titanomagnetite, +/-clinopyroxene+/-ilmenite, with minor additions of quartz and angular felsic to mafic volcanic lithic clasts. The crystal composition suggests an andesitic to dacitic volcanic provenance. Crystal-rich volcaniclastic facies containing approximately 1-5% titanomagnetite, dominate in this member which gives it a characteristically high magnetic signature relative to the surrounding units.  Carbonate units mark the base of the Tyndall Group (Lynchford Member) at Comstock (Corbett et al. 1974) and in parts of the Anthony Road area (around Howards Anomaly). In one Comstock drill hole (C50), the main carbonate unit contains shallow marine fossils including trilobites, small echinoderm plates, hyolithids, gastropods and inarticulate brachiopods (Jago et al. 1972).  At Comstock the basal carbonates are overlain by other facies of the Lynchford Member including laminated mudstone and volcaniclastic lithic breccia. Details are given in White and McPhie (in prep).|16-MAY-23
29474|Lynchford Member|Relationships and boundaries|The character of the lower contact (to older underlying rocks) appears to be conformable in some areas (e.g. Comstock, Anthony Road) where an interfingering contact to the underlying andesite units is observed. In some areas the Lynchford Member is interpreted to rest unconformably on, or in fault contact with older rocks of the Mount Read Volcanics (e.g. Lynchford). At Lynchford the Lynchford Member lies to the west of older Yolande River Sequence rocks (contact not exposed) and overlaps a large exposure of mafic rocks (Lynch Creek Basalt). In other areas the contact is poorly defined due to poor exposure.  The quartz-poor (andesitic to dacitic) crystal-rich volcaniclastic units of the Lynchford Member grade upwards into more felsic (dacitic to rhyolitic) quartz-rich units of the Mount Julia Member at a number of locations (Zig Zag Hill, Comstock, Anthony Road). The contact between these members is gradational and interfingering, and largely based on a very subtle compositional variation up-sequence. The Lynchford Member generally contains a lower proportion of laminated mudstone/sandstone units relative to the Mount Julia Member. At Lynchford, the Tyndall Group sequence is incomplete and the Lynchford Member is unconformably overlain by siliciclastic sandstone, interpreted as Pioneer Beds of the upper Owen Conglomerate (Corbett et al. 1989).|16-MAY-23
29474|Lynchford Member|Age reasons|The age is constrained by fossil dating. Fossiliferous carbonate (limestone) units in the Lynchford Member at Comstock contain fauna dated as late Middle to early Late Cambrian age (jago et al. 1972).|16-MAY-23
29474|Lynchford Member|Proposed publication|Australian Journal of Earth Sciences|16-MAY-23
29474|Lynchford Member|References|79/20563; 79/00954;00/30190|16-MAY-23
29474|Lynchford Member|Category|1|16-MAY-23
36812|Mathinna Supergroup|Name source|The Supergroup is named after the old gold mining town of Mathinna (in accord with Powell et al., 1993).|16-MAY-23
36812|Mathinna Supergroup|Unit history|Mathinna Beds (Banks 1962), Mathinna Group (Powell et al. 1993)|16-MAY-23
36812|Mathinna Supergroup|Constituents|Rocks west of the Scottsdale batholith (Australian Map Grid; AUS66; 55G; 550000mE, 5440000mN) include the Tippogoree and Panama Groups. The Tippogoree Group includes the Stony Head Sandstone and Turquoise Bluff Slate, whereas the Panama Group comprises the Bellingham Formation and Sidling sandstone. Rocks east of the Scottsdale batholith remain undifferentiated Mathinna Supergroup.|16-MAY-23
36812|Mathinna Supergroup|Geomorphic expression|Typically topographically upstanding where contact metamorphosed. Elsewhere, variably incised and eroded.|16-MAY-23
36812|Mathinna Supergroup|Type section locality|None specified.|16-MAY-23
36812|Mathinna Supergroup|Extent|All pre-Late Carboniferous sedimentary rocks cropping out in northeastern Tasmania south to the Forestier Peninsula, and north into the Furneaux Group of islands in Bass Strait.|16-MAY-23
36812|Mathinna Supergroup|Thickness range|Inferred to be about 7km (Powell & Baillie, 1992).|16-MAY-23
36812|Mathinna Supergroup|Lithology|Succession of turbiditic sandstone and mudstone. Sandstone composition varies from quartzose sublitharenite to feldspathic litharenite.|16-MAY-23
36812|Mathinna Supergroup|Depositional environment|Upper parts (Panama Group and equivalent rocks east of Scottsdale batholith) deposited as turbidites in basinal setting (Powell et al., 1993). Lower parts (Tippogoree Group) also turbiditic although basin geometry remains unknown.|16-MAY-23
36812|Mathinna Supergroup|Fossils|There are only two fossil localities west of the Scottsdale batholith where the stratigraphy has been formally subdivided (Powell et al., 1993). One site in the Turquoise Bluff Slate yielded two poorly preserved graptolites of Early to Middle Ordovician (Bendigonian Be1 to Darriwillian Da3) age (Banks & Smith, 1968; VandenBerg pers comm.). A second site further east and higher in the stratigraphy (Sidling sandstone) contains ?Devonian plant fragments (Banks, 1962; Powell et al., 1993). East of the Scottsdale batholith the stratigraphy remains undifferentiated, with a small number of fossil locations indicating a predominantly Silurian to Early Devonian age for turbidite deposition.|16-MAY-23
36812|Mathinna Supergroup|Diastems or hiatuses|Cross-cutting structures and associated fabrics show older Tippogoree Group rocks have been deformed prior to Panama deposition. The contact between the Tippogoree and Panama Groups does not crop out, however, the simpler structural history in younger rocks indicates the likelihood of a hidden unconformity between the Tippogoree and Panama Groups.|16-MAY-23
36812|Mathinna Supergroup|Relationships and boundaries|No base is known and the top is an erosional contact at an angular unconformity with the overlying Early Devonian (Emsian) St Marys Porphyrite (Powell et al., 1993).|16-MAY-23
36812|Mathinna Supergroup|Age reasons|The Turquoise Bluff Slate contains the oldest fossils, comprising two poorly preserved graptolites of Early to Middle Ordovician (Bendigonian Be1 to Darriwillian Da3) age (Banks & Smith, 1968; VandenBerg pers comm.). Deposition ended before emplacement of the St Marys Porphyrite at 388+/-1Ma (Rb-Sr; Turner et al., 1986).|16-MAY-23
36812|Mathinna Supergroup|Proposed publication|Australian Journal of Earth Sciences|16-MAY-23
36812|Mathinna Supergroup|References|*BANKS M.R. 1962. The Silurian and Devonian Systems. Journal of the Geological Society of Australia 9, 177-188.     *97/28855 - BANKS, M. & SMITH A. 1968. A graptolite from the Mathinna Beds, northeastern Tasmania. Australian Journal of Science 31, 118-119.     *POWELL, C. McA. & BAILLIE, P.W. 1992. Tectonic affinity of the Mathinna Group in the Lachlan Fold Belt. Tectonophysics 214, 193-209.      *94/27811 - POWELL, C. McA., BAILLIE,  P.W., CONAGHAN, P. J. & TURNER, N. J. 1993. The mid-Palaeozoic turbiditic Mathinna Group, NE Tasmania. Australian Journal of Earth Sciences 40, 169-198.      *86/25572 - TURNER, N. J., BLACK, L. P. & HIGGINS, N. C. 1986. The St Marys Porphyrite - a Devonian ash-flow tuff and its feeder. Australian Journal of Earth Sciences 33, 201-218.|16-MAY-23
24391|Mount Anne Group|Name source|Mt Anne [DN530451], Wedge 1:100 000 Sheet.|16-MAY-23
24391|Mount Anne Group|Constituents|Twin Creeks Formation, Lake Judd Formation, Sarah-Jane Quartzite, Lonely Tarns Formation.|16-MAY-23
24391|Mount Anne Group|Extent|The unit is exposed over approximately 50 km2 in the Mt Anne-Lake Judd area, in the southeastern part of the Wedge 1:100 000 Sheet.|16-MAY-23
24391|Mount Anne Group|Thickness range|Approximately 3 km; uncertain due to faulting.|16-MAY-23
24391|Mount Anne Group|Lithology|Orthoquartzite, quartz siltstone, and pelite with minor dolomite. The unit is regionally metamorphosed to lower greenschist facies: pelite is generally phyllite or slate.|16-MAY-23
24391|Mount Anne Group|Relationships and boundaries|The base of the unit is obscured by Quaternary cover. The youngest known parts of the unit are faulted against Precambrian Pandani Group.|16-MAY-23
24391|Mount Anne Group|Age reasons|Late Precambrian, due to tectonometamorphic grade and regional geological setting (see Turner, 1989).|16-MAY-23
24391|Mount Anne Group|Proposed publication|Explanatory Report, Department of Mines, Tasmania: Pedder 1:50 000 Sheet|16-MAY-23
24391|Mount Anne Group|Category|2|16-MAY-23
24392|Mount Bowes Formation|Name source|Mt Bowes [DN517548], Wedge, 1:100 000 Mapsheet.|16-MAY-23
24392|Mount Bowes Formation|Type section locality|Approximately 500 m of quartzarenite, siltstone, red mudstone and minor quartzitic conglomerate between DN523535 and DN529540. The section dips SW and is overturned. The conglomerate, about 40 m thick, marks the base of the unit.|16-MAY-23
24392|Mount Bowes Formation|Extent|The unit is exposed on Mt Bowes and on strike ridges to the south as far as DN518515. The unit is indicated on the Pedder 1:50 000 geological map by the symbol Pss.|16-MAY-23
24392|Mount Bowes Formation|Thickness range|Approximately 500 m.  |16-MAY-23
24392|Mount Bowes Formation|Lithology|Quartzarenite, siltstone, and red mudstone with quartzitic conglomerate at the base.|16-MAY-23
24392|Mount Bowes Formation|Relationships and boundaries|Belongs to Pandani Group. Probably conformably overlies Huon River Formation (contact not observed). Youngest exposed parts of unit are faulted against Precambrian Weld River Group.|16-MAY-23
24392|Mount Bowes Formation|Age reasons|Late Precambrian (as for Pandani Group).|16-MAY-23
24392|Mount Bowes Formation|Proposed publication|Explanatory Report, Department of Mines, Tasmania, for Pedder 1:50 000 Mapsheet. |16-MAY-23
29473|Mount Julia Member|Name source|Initial Statement: The Mount Julia Member is the upper member of two members in the Comstock Formation. The Comstock Formation is the lowermost of two formations in the Tyndall Group. The term 'Mount Julia' was chosen as it is the closest geographical location to the type section location (Anthony Road), that has not been already used for stratigraphic naming.                                                                     Mount Julia (AMG Grid Reference 5361600N - 380800E, Selina sheet, Tasmania 1:25 000 series topographical map, Tasmanian Lands Department). Mount Julia is located approximately 2-3 km north of the type section (Anthony Road).|16-MAY-23
29473|Mount Julia Member|Unit history|None|16-MAY-23
29473|Mount Julia Member|Type section locality|The type section is situated along the Anthony Road between the Tyndall Creek overpass and the Howards Road turnoff. The Mount Julia Member is steeply dipping, facing east and is exposed between 5357300N - 381050E (base) and 5358650N - 381040E (top) (AMG Grid References, Tyndall sheet, Tasmania 1:25 000 series topographical map, Tasmanian Lands Department).|16-MAY-23
29473|Mount Julia Member|Extent|The Mount Julia Member occurs from the Mount Lyell district to the Anthony Road, Henty Canal and Moxon Saddle areas. Correlates of the Mount Julia Member occur further north in the Mount Cripps Subgroup (Corbett 1992) in the Cradle Mountain Link Road area and in the Winterbrook area (Pemberton and Vicary 1989). Correlates may also occur further south in the Jukes-Darwin area (Corbett 1992). However, some of these units are more recently interpreted as part of the Eastern quartz-phyric sequence (Corbett et al. 1993).|16-MAY-23
29473|Mount Julia Member|Thickness range|The Mount Julie Member ranges in thickness from approximately 150 m (Comstock area) to 750 m (Henty Canal, Cradle Mountain Link Road area). Incomplete thinner sequences are also present in places (e.g. Mount Lyell Mill area, Corbett et al. 1974). The Mount Julia Member is approximately 390 m thick at the type section locality along the Anthony Road.|16-MAY-23
29473|Mount Julia Member|Lithology|The Mount Julia Member is quartz-rich (rhyolitic to dacitic) in character and comprises four main facies:  1) crystal-rich volcaniclastic sandstone;  2) massive to normally graded volcaniclastic breccia-sandstone units;  3) welded ignimbrite (including ignimbrite clast volcaniclastic breccia);  4) coherent rhyolite and associated rhyolite breccia. Minor laminated fine sandstone/mudstone units also occur in the Mount Julia Member in places.  Details are given in White and McPhie (in prep).  Crystal-rich volcaniclastic sandstone (CRVS) is the most common facies in the Mount Julia Member and comprises a closed framework of dominantly plagioclase and quartz crystals and crystal fragments (35-70%), with minor titanomagnetite+/-ilmenite+/-hornblende grains in a fine grained altered matrix. Minor additions of pebble to cobble size, angular to rounded lithic fragments (dominantly felsic volcanic clasts) also occur in places. The Mount Julia Member also contains tabular, normally graded volcaniclastic breccia/sandstone units (m's to 10's m thick) that are intercalated with massive CRVS units. They comprise volcaniclastic lithic breccia near the base grading up into massive CRVS, with laminated fine sandstone+/-mudstone at the top and are interpreted as subaqueous mass-flow units. Crystal-rich volcaniclastic facies containing approximately 1-3% titanomagnetite, dominate in this member which gives it a characteristically high magnetic signature relative to other surrounding rocks.|16-MAY-23
29473|Mount Julia Member|Relationships and boundaries|The quartz-poor (andesitic to dacitic) crystal-rich volcaniclastic units of the underlying Lynchford Member grade upwards into more felsic (dacitic to rhyolitic) quartz-rich units of the Mount Julia Member at a number of locations (Zig Zag Hill, Comstock, Anthony Road). The contact between thse members is gradational and interfingering, and largely based on a very subtle compositional variation up-sequence. At East Mount Lyell, the Mount Julia Member rests directly on older felsic volcanic units interpreted as part of the Eastern quartz-phyric sequence (Corbett 1992).  In areas of good exposure (e.g. Comstock, Anthony Road, Henty Canal), the upper contact of t6he Comstock Formation (with the overlying Zig Zag Hill Formation) is gradational and conformable. However, at Zig Zag Hill a sharp contact between the welded ignimbrite unit (top of the Mount Julia Member) and the overlying Zig Zag Hill Formation suggests that some erosion occurred prior to deposition of the Zig Zag Hill Formation. This contact is interpreted as a parallel unconformity.|16-MAY-23
29473|Mount Julia Member|Age reasons|Marine fossils found in a brown mudstone unit within the 'Mount Julia Member of the Comstock Formation correlates' on the Cradle Mountain Link Road are dated as late Middle Cambrian in age (Lejopyge laevigata II and III to Damesella torosa-Ascionepea janitrix zones) (Pemberton et al. 1991). The age range of these fossils is approximately 530 to 520 Ma (Shergold 1989). The fossiliferous carbonate (limestone) unit in the underlying Lynchford Member of the Comstock Formation at Comstock contains fauna of a similar age (late Middle to early Late Cambrian age: Jago et al. 1972). Recent isotopic U-Pb dating of magmatic zircons from 2 crystal-rich volcaniclastic sandstone samples in the Mount Julia Member gave two relatively young dates of 494.4+/-3.8 Ma and 502.5+/-3.3 Ma (Perkins and Walshe 1993).|16-MAY-23
29473|Mount Julia Member|Proposed publication|Australian Journal of Earth Sciences|16-MAY-23
29473|Mount Julia Member|References|95/28064; 79/00954; 96/28186; RC89/031; 00/30190.|16-MAY-23
36814|Panama Group|Name source|After Panama Ridge (GDA94 Zone 55, 523830 mE, 5440000 mN)|16-MAY-23
36814|Panama Group|Name source|After Panama Ridge (Australian Map Grid; AUS66; 55G; 524000mE, 5440000mN).|16-MAY-23
36814|Panama Group|Constituents|Bellingham Formation and (informally defined) Sidling sandstone (Powell et al., 1993).|16-MAY-23
36814|Panama Group|Constituents|Yarrow Creek Mudstone, Retreat Formation, Lone Star Siltstone, Sideling Sandstone and Scamander Formation. Note, Sideling Sandstone and Scamander Formation are partial lateral equivalents of each other.|16-MAY-23
36814|Panama Group|Geomorphic expression|Variable, from dissected undulating low to mid-level plateau country on the pelitic formations, to higher dissected hilly to ridge country on the sandstone-rich units and within contact metamorphic zones adjacent to mid-Devonian granitoids.|16-MAY-23
36814|Panama Group|Type section locality|No single type locality specified. Refer to type locality information for constituent formations.|16-MAY-23
36814|Panama Group|Type section locality|None specified, but typical outcrops occur on the Bridport to Georgetown road between about 508600mE, 5451400mN and 533000mE, 5459000mN (Australian Map Grid; AUS66; 55G) and on the Tasman Highway where it crosses the Sidling Range at about 537000mE, 5433000mN.|16-MAY-23
36814|Panama Group|Extent|As noted above, may occupy all of the Mathinna Supergroup outcrop area east of the currently known extent of the Tippogoree Group in NE Tasmania.|16-MAY-23
36814|Panama Group|Extent|Pre-Late Carboniferous sedimentary rocks cropping out southeast of Pipers River where it crosses the Bridport to Georgetown road at 508600mE, 5451400mN (Australian Map Grid; AUS66; 55G) and east of granitic rocks of the Scottsdale batholith (550000mE, 5440000mN).|16-MAY-23
36814|Panama Group|General description|Alternating megasequences of dominantly thin bedded mudstone-siltstone with minor or subordinate sandstone (Yarrow Creek Mudstone, Lone Star Siltstone) and quartz-rich sandstone-dominated turbidites deposited in submarine fan complexes (Retreat Formation, Sideling Sandstone, Scamander Formation).|16-MAY-23
36814|Panama Group|Thickness range|Estimated from structural sections, in the range 4500 - 6000 m (but top not exposed)|16-MAY-23
36814|Panama Group|Thickness range|Unknown.|16-MAY-23
36814|Panama Group|Lithology|Thin-bedded mudstone-siltstone with generally minor fine-grained quartz-rich sandstone, or medium- to thick-bedded quartz-rich sandstone (commonly classical Bouma turbidites) with generally minor interbedded shale-mudstone-siltstone.|16-MAY-23
36814|Panama Group|Lithology|Classical turbidites, comprising upwardly fining mudstone to predominantly fine- to medium-, rarely coarse-grained quartzose sandstone (Powell et al., 1993).|16-MAY-23
36814|Panama Group|Depositional environment|Marine, alternating between background to distal turbidite pelitic sedimentation, and sandy turbidite-dominated deposition in overlapping and coalescing submarine fan complexes.|16-MAY-23
36814|Panama Group|Depositional environment|Basinal setting with sediment deposited as turbidites (Powell et al., 1993)|16-MAY-23
36814|Panama Group|Fossils|late Silurian (Ludlow) graptolites in Lone Star Siltstone; late Silurian and Early Devonian plant fossils in Sideling Sandstone; Early Devonian plant fossils, graptolites and marine macrofossils in Scamander Formation.|16-MAY-23
36814|Panama Group|Fossils|Vascular plant remains in the Sidling sandstone (Banks, 1962).|16-MAY-23
36814|Panama Group|Relationships and boundaries|The base of the unit is characterised by a change from strongly cleaved and recumbently folded Turquoise Bluff Slate to open upright folded classical turbidites of the Bellingham Formation. The top of the unit has not been defined.|16-MAY-23
36814|Panama Group|Relationships and boundaries|Inferred fault contact with, and inferred unconformable relationship with, Ordovician Turquoise Bluff Slate. Distinguished from high-strain recumbently folded generally non-turbiditic pelitic slate of the Turquoise Bluff Slate by an abrupt change to low-medium strain upright-folded turbidite-dominated facies of the Panama Group. Stratigraphic top not exposed, but is unconformably overlain by extrusive Middle Devonian St Marys Porphyry or intruded by Middle Devonian granitoids.|16-MAY-23
36814|Panama Group|Identifying features|Sandy turbidite-bearing megasequence containing Silurian to Early Devonian fossils and lacking Ordovician fossils and high-strain recumbent fold structures.|16-MAY-23
36814|Panama Group|Structure and Metamorphism|Generally upright to steeply inclined open to close folds with a tendency to chevron morphology, associated moderately to steeply dipping thrust faults, and moderately developed axial plane cleavages. Regional metamorphic grade is dominantly anchizonal (200-300 degrees C, sub-greenschist facies) (Patison et al., 2001). Contact metamorphism in aureoles around mid-Devonian granitoids reaches hornblende hornfels facies.|16-MAY-23
36814|Panama Group|Age reasons|This unit overlies rocks containing poorly preserved graptolites of Early to Middle Ordovician (Bendigonian Be1 to Darriwillian Da3) age (Banks & Smith, 1968; VandenBerg pers comm.). The Sidling sandstone contains vascular plant remains of Devonian age (Banks, 1962).|16-MAY-23
36814|Panama Group|Age reasons|Inferred unconformable relationship with Ordovician Turquoise Bluff Slate. Contains Late Silurian graptolites, and Early Devonian plant, graptolite and marine macrofossils. Unconformably overlain by Middle Devonian extrusive St Marys Porphyry (Rb-Sr age 388 ± 1 Ma, Turner et al., 1986).|16-MAY-23
36814|Panama Group|Correlations|May occupy all of the Mathinna Supergroup outcrop area east of the currently known extent of the Tippogoree Group; however second-generation regional mapping (at 1:25,000 scale) needs to be completed to be sure of this.|16-MAY-23
36814|Panama Group|Alteration and Mineralisation|The Panama Group is host to important orogenic gold mineralisation associated with the last major phase of Devonian deformation.|16-MAY-23
36814|Panama Group|Geophysical Expression|Variable. Characterised in some areas on K-Th-U (RGB) radiometric imagery by lack of response in all channels (i.e. dark image) over sandstone-rich units, and strong response in all channels (i.e. bright image) over pelite-rich units. However this is not a general rule, partially due to response modification by contact metamorphism.|16-MAY-23
36814|Panama Group|Geochemistry|On standard discrimination diagrams, geochemical signatures show clear indications of a dominantly passive margin sedimentary environment with a quartzose sedimentary provenance.|16-MAY-23
36814|Panama Group|Defn author|David Seymour, Mineral Resources Tasmania, 10-SEP-2010.|16-MAY-23
36814|Panama Group|Defn author|? Mineral Resources Tasmania, approved S. Forsyth 3-JUL-2003|16-MAY-23
36814|Panama Group|Defn author|David Seymour, MRT, Stephen Forsyth 7-SEP-2010|16-MAY-23
36814|Panama Group|Proposed publication|Seymour, D. B.; Woolward, I. R.; McClenaghan, M. P. 2010. Stratigraphic revision and re-mapping of the Mathinna Supergroup west of the Scottsdale Batholith, Northeast Tasmania. Mineral Resources Tasmania, 1:25 000 Scale Digital Geological Map Series Explanatory Report 4.|16-MAY-23
36814|Panama Group|References|Patison, N. L.; Berry, R. F.; Davidson, G. J.; Taylor, B. P.; Bottrill, R. S.; Manzi, B.; Ryba, J.; Shepherd, R. E. 2001. Regional metamorphism of the Mathinna Group, northeast Tasmania. Australian Journal of Earth Sciences 48: 281-292.Turner, N. J.; Black, L. P.; Higgins, N. C. 1986. The St Marys Porphyrite and related dykes - a Devonian intra-caldera ignimbrite and its feeder. Australian Journal of Earth Sciences 33: 201-218.|16-MAY-23
36814|Panama Group|References|BANKS, M. 1962. The Silurian and Devonian Systems. Journal of the Geological Society of Australia 9, 177-188. BANKS, M. & SMITH A. 1968. A graptolite from the Mathinna Beds, northeastern Tasmania. Australian Journal of Science 31, 118-119.  POWELL, C. McA., BAILLIE,  P.W., CONAGHAN, P. J. & TURNER, N. J. 1993. The mid-Palaeozoic turbiditic Mathinna Group, NE Tasmania. Australian Journal of Earth Sciences 40, 169-198.|16-MAY-23
24450|Pandani Group|Name source|Pandani Shelf [DN533460], Wedge 1:100 000 Mapsheet.|16-MAY-23
24450|Pandani Group|Constituents|Lot Formation, Huon River Formation, Mt Bowes Formation.|16-MAY-23
24450|Pandani Group|Extent|The unit is exposed over ca. 40 km2 in the southeastern part of the Wedge 1:100 000 Mapsheet around the headwaters of the Huon River.|16-MAY-23
24450|Pandani Group|Thickness range|Approximately 4 km; uncertain due to faulting.|16-MAY-23
24450|Pandani Group|Lithology|Pelite (phyllite, slate or mudstone) with interlayered dolomite; lesser quartzarenite.|16-MAY-23
24450|Pandani Group|Relationships and boundaries|The oldest known parts of the unit are in faulted juxtaposition with Late Precambrian Mt Anne Group. The unit is unconformably overlain by late Precambrian Weld River Group and by a lithiwacke sequence of probable Cambrian age (Calver, in press).|16-MAY-23
24450|Pandani Group|Age reasons|Late Precambrian (Calver, in press).|16-MAY-23
24450|Pandani Group|Proposed publication|Explanatory Report, Department of Mines, Tasmania, for Pedder 1:50 000 Mapsheet|16-MAY-23
24450|Pandani Group|References|90/26830|16-MAY-23
75364|Retreat Formation|Name source|Named after the small settlement of Retreat: GDA94 Zone 55, 514480 mE, 5444050 mN|16-MAY-23
75364|Retreat Formation|Unit history|Along with the Lone Star Siltstone and Yarrow Creek Mudstone , replaces the Bellingham Formation (Strat No. 1426, of the former Mathinna Group)|16-MAY-23
75364|Retreat Formation|Constituents|None.|16-MAY-23
75364|Retreat Formation|Geomorphic expression|Undulating, elevated to hilly ground. Generally more positive geomorphic expression than immediately underlying or overlying units.|16-MAY-23
75364|Retreat Formation|Type section locality|The main type area is nominated as Bare Hill Road and its spur roads, between the intersection with Golconda Road (GDA94 Zone 55: 520700 mE, 5443170 mN) and a point some 5.6 km to the north (GDA94 Zone 55: 521565 mE, 5448730 mN), along which representative folded sections through the more sandstone-rich parts of the formation are exposed. Folded reference sections exposing parts of the formation with more interbedded siltstone-mudstone are intermittently exposed on Retreat Road between a point (GDA94 Zone 55: 513860 mE, 5445420 mN) some 1.5 km north of Retreat, to the intersection with the Bass Highway some 7 km to the north (GDA94 Zone 55: 512780 mE, 5452270 mN).|16-MAY-23
75364|Retreat Formation|Description at type locality|Interbedded turbiditic medium- to fine-grained quartz-rich sandstone with generally minor interbedded siltstone-mudstone. Reference sections on Retreat Road show a higher proportion of interbedded siltstone-mudstone, and lower proportion of medium-grained sandstone. Thickness: Estimated from structural profiles: about 1,050 m.|16-MAY-23
75364|Retreat Formation|Extent|Currently mapped geographic extent comprises a more or less continuous, sinuous outcrop belt up to 8 km wide, exending from near Bellingham on the Bass Strait coast in the north, some 29 km to near Lilydale in the south.|16-MAY-23
75364|Retreat Formation|General description|Parent unit: Panama Group (of the Mathinna Supergroup).|16-MAY-23
75364|Retreat Formation|Thickness range|Faulted contacts against adjacent units in several areas make assessment of variations in stratigraphic thickness difficult. Structural profile sections suggest stratigraphic thickness may be reasonably consistent at about 1,050 m.|16-MAY-23
75364|Retreat Formation|Lithology|Sandstone-rich parts of the formation (e.g. in the type area) contain graded beds up to 2 m thick of quartz-rich medium-fine grained sandstone commonly showing Bouma A-B-C bed subdivisions, with interbedded combinations of typically thinner-bedded quartzose siltstone (commonly cross-laminated), laminated mudstone and shale. These sections typically have ratios >/=2:1 of sandstone : siltstone-mudstone-shale. Less sandstone-rich sections (e.g. in the reference area) are thinner bedded (</=0.5 m) and typically comprise interbedded fine-very fine grained quartz-rich sandstone, siltstone, grey mudstone and shale with ratios of sandstone : siltstone-mudstone-shale of about 1:1, although some outcrops may show a paucity or absence of sandstone. Some sandstone beds and bed sequences in these sections are massive or plane laminated, but are lacking in grading or other classical Bouma turbidite bed structures.|16-MAY-23
75364|Retreat Formation|Depositional environment|Marine, probably largely deposited in one or more sandy submarine fan complexes.|16-MAY-23
75364|Retreat Formation|Fossils|None.|16-MAY-23
75364|Retreat Formation|Diastems or hiatuses|None known.|16-MAY-23
75364|Retreat Formation|Relationships and boundaries|Map relationships, bedding measurements and facing evidence indicate apparently conformable relationships with both the underlying Yarrow Creek Mudstone and the overlying Lone Star Siltstone. Both contacts are probably abrupt transitions (i.e. over a few metres of section).|16-MAY-23
75364|Retreat Formation|Identifying features|The Retreat Formation is distinguished from the underlying and overlying formations largely by its high percentage of turbiditic quartz-rich sandstone beds. The other main distinguishing characteristic is a geophysical one - i.e. a dark (approaching black) signature on K-Th-U RGB images of airborne radiometric data, which is probably partly due to a paucity of response in all three channels due to the high quartz sandstone content and partly due to the quartz sand-rich soils which derive from weathering of the unit and blanket its outcrop area.|16-MAY-23
75364|Retreat Formation|Structure and Metamorphism|Structural style is upright to steeply inclined, generally open to close folds with variably developed axial planar sandstone cleavage (showing conjugate geometry in some outcrops), and well developed axial planar penetrative slaty cleavage in the finer-grained lithologies. Later folds with axial planar crenulation cleavage in the finer-grained lithologies present in some areas. Metamorphism is anchizonal (200-300 degrees C, sub-greenschist facies) according to Patison et al. (2001).|16-MAY-23
75364|Retreat Formation|Age reasons|Probably Silurian. The overlying Lone Star Siltstone contains late Silurian (Ludlow) graptolites, and the Panama Group which this unit is part of is in fault or faulted unconformity contact with the underlying Turquoise Bluff Slate which contains Early Ordovician graptolites.|16-MAY-23
75364|Retreat Formation|Correlations|Correlates possibly exist elsewhere within the Mathinna Supergroup outcrop area but none have been confirmed at this stage.|16-MAY-23
75364|Retreat Formation|Alteration and Mineralisation|Devonian gold mineralisation in the Denison Goldfield is spatially associated with the contact between this unit and the overlying Lone Star Siltstone.|16-MAY-23
75364|Retreat Formation|Geophysical Expression|Distinctive dark signature on K-Th-U RGB images of airborne radiometric data, i.e. weak signal in all three channels.|16-MAY-23
75364|Retreat Formation|Geochemistry|No data.|16-MAY-23
75364|Retreat Formation|Defn author|David Seymour Mineral Resources Tasmania, 7-SEP-2010.|16-MAY-23
75364|Retreat Formation|Proposed publication|Seymour, D. B.; Woolward, I. R.; McClenaghan, M. P. 2010. Stratigraphic revision and re-mapping of the Mathinna Supergroup west of the Scottsdale Batholith, Northeast Tasmania (Explanatory Report for parts of 1:25 000 scale map sheets Low Head, Tam O'Shanter, Weymouth, Retreat, Lilydale, Bridport, Bowood, Nabowla, Lisle and Patersonia). Mineral Resources Tasmania, 1:25 000 Scale Digital Geological Map Series Explanatory Report 4.; possibly also AJES.|16-MAY-23
75364|Retreat Formation|References|Patison, N. L.; Berry, R. F.; Davidson, G. J.; Taylor, B. P.; Bottrill, R. S.; Manzi, B.; Ryba, J.; Shepherd, R. E. 2001. Regional metamorphism of the Mathinna Group, northeast Tasmania. Australian Journal of Earth Sciences 48, 281-292. [RefID 23167]|16-MAY-23
74933|Robbins Creek Formation|Name source|Robbins Creek, eastern King Island.|16-MAY-23
74933|Robbins Creek Formation|Unit history|'Laminated siltstone' unit of Waldron & Brown (1993).|16-MAY-23
74933|Robbins Creek Formation|Geomorphic expression|No distinctive geomorphic expression; more erodible than enclosing units and tends to be intermittently exposed in creeks and not exposed on interfluves.|16-MAY-23
74933|Robbins Creek Formation|Type section locality|A 200 metre creek section in the lower reaches of Robbins Creek, centred on Lat. 39.966 degrees S, 144.126 degrees E.|16-MAY-23
74933|Robbins Creek Formation|Description at type locality|Grey-green to black, interlaminated shale and siltstone, with minor units (probably flows) of plagioclase-rich, altered basalt.  The beds dip and face moderately east, and there is a weak subvertical tectonic cleavage.  Near the top, the formation is intruded by an intermediate sill (Grimes Intrusive Suite) about 80 m thick. The topmost beds, exposed above the sill, include thin beds of impure limestone.  Overall, the section is incompletely exposed (about 50%) and the contacts are not exposed.|16-MAY-23
74933|Robbins Creek Formation|Extent|Exposed over a strike length of about 8 km from just south of Barrier Creek to Cottons Creek, eastern King Island.  A contact metamorphosed/metasomatised equivalent is probably present in the Grassy Mine area and further west.|16-MAY-23
74933|Robbins Creek Formation|Thickness range|Approximately 100 m.|16-MAY-23
74933|Robbins Creek Formation|Lithology|Interlaminated shale and siltstone with minor altered basalt flows; a few metres of basal conglomerate is locally present, e.g. Yarra Creek.|16-MAY-23
74933|Robbins Creek Formation|Depositional environment|Probably marine, deeper than storm wave base.|16-MAY-23
74933|Robbins Creek Formation|Diastems or hiatuses|Basal unconformity.  No others known.|16-MAY-23
74933|Robbins Creek Formation|Relationships and boundaries|Basal unconformity upon the Fraser Formation; conformable or disconformable upper contact with Cottons Breccia.|16-MAY-23
74933|Robbins Creek Formation|Age reasons|Cryogenian.  Unconformably overlies Fraser Formation of uncertain (Mesoproterozoic or early Neoproterozoic) age; conformably or disconformably overlain by Cottons Breccia which is terminal Cryogenian in age (Calver et al., 2004).|16-MAY-23
74933|Robbins Creek Formation|Correlations|Probably correlates with the lower part of the Kanunnah Subgroup of north-west Tasmania.|16-MAY-23
74933|Robbins Creek Formation|Proposed publication|Calver, C.R. , 2008 (Compiler). Digital Geological Atlas 1:25,000 series, Sheet 2456. Grassy. Mineral Resources Tasmania.|16-MAY-23
74933|Robbins Creek Formation|Comments|The thin-bedded chloritic siltstones and shales are distinct from the thick-bedded mudstone and siliceous siltstone of the underlying Fraser Formation.  The overlying Cottons Breccia is a distinctive diamictite.  The beds dip moderately east and the rocks are of sub-greenschist metamorphic facies.|16-MAY-23
74933|Robbins Creek Formation|References|Calver, C.R., Black, L.P., Everard, J.L. and Seymour, D.B., 2004. U-Pb zircon age constraints on late Neoproterozoic glaciation in Tasmania. Geology, 32(10): 892-896.Calver, C.R. , 2008 (Compiler). Digital Geological Atlas 1:25,000 series, Sheet 2456. Grassy. Mineral Resources Tasmania.Waldron, H.M., and Brown, A.V., 1993: Geological setting and petrochemistry of Eocambrian-Cambrian volcano-sedimentary rock sequences from southeast King Island, Tasmania.  Mineral Resources Tasmania Report 1993/28.|16-MAY-23
74933|Robbins Creek Formation|Parent|Grassy Group.|16-MAY-23
74933|Robbins Creek Formation|Proposer|C.R. Calver. 2008|16-MAY-23
74932|Sandblow Granite|Name source|Sandblow Point, southeast coast of King Island.|16-MAY-23
74932|Sandblow Granite|Unit history|Grassy Granite (e.g. Chappell et al., 1991; Black et al., 2005);  Grassy Granodiorite (e.g. Large, 1971; Kwak & Tan, 1981; Solomon, 1981; Burrett & Martin, 1989;  Blevin & Chappell, 1995);Grassy Monzogranite (Wesolowski et al., 1984).|16-MAY-23
74932|Sandblow Granite|Geomorphic expression|Bold coastal outcrop along most of coastal section; inland, the granite is low-lying and poorly outcropping.|16-MAY-23
74932|Sandblow Granite|Type section locality|Coastal outcrops around Sandblow Point, Grassy Harbour, Jetty Point, and the southern side of the Grassy Open-Cut Mine, extending from 40.077 degrees S, 144.046 degrees E, to 40.074 degrees S, 144.056 degrees E.|16-MAY-23
74932|Sandblow Granite|Description at type locality|Prominent outcrops of massive, jointed, undeformed, pale grey, porphyritic monzogranite.|16-MAY-23
74932|Sandblow Granite|Extent|Southeast coast of King Island between Grassy Harbour and Red Hut Point and inland a few kilometres, cropping out over a total area (including some surficial sand cover) of about 20 sq. km.|16-MAY-23
74932|Sandblow Granite|Lithology|Porphyritic monzogranite. with 10% to 15% euhedral alkali-feldspar phenocrysts up to 2 cm by 3 cm by 1 cm, in a coarse groundmass with average grain size of around 2 mm to 3 mm.  The groundmass consists of quartz, oligoclase, alkali feldspar, biotite and hornblende (Wesolowski et al., 1983).|16-MAY-23
74932|Sandblow Granite|Relationships and boundaries|The Sandblow Granite has transgressive, intrusive contacts with the Fraser Formation and Grassy Group, both of Proterozoic age.|16-MAY-23
74932|Sandblow Granite|Age reasons|Dated at 350.8 ± 1.7 Ma  (early Carboniferous) (SHRIMP U-Pb on zircon) (Black et al., 2005), from a locality near the southern side of the open-cut mine.|16-MAY-23
74932|Sandblow Granite|Correlations|This is the youngest of the widespread mid-Devonian to early Carboniferous Tasmanian granites.   A small body of similar granite 5 km to the northeast of the type locality may be a faulted outlier of the Sandblow Granite, but has been given a separate name by many workers (Bold Head Granite).|16-MAY-23
74932|Sandblow Granite|Proposed publication|Calver, C.R. , 2008 (Compiler). Digital Geological Atlas 1:25,000 series, Sheet 2456. Grassy. Mineral Resources Tasmania.Black, L.P.; J.L. Everard, M. P. McClenaghan, R. J. Korsch, A.-M. Fioretti, A. V. Brown  and C. Foudoulis  (in preparation): Inherited zircon and isotopic evidence for the origin of Tasmanian Devonian-Carboniferous granites. Australian Journal of Earth Science.|16-MAY-23
74932|Sandblow Granite|Comments|The Sandblow Granite was for many years known as the Grassy Granite, Granodiorite, etc. (see Synonymy) but the term 'Grassy Group' has priority (Knight & Nye, 1953) and is applied to the nearby Neoproterozoic stratigraphic sequence, necessitating renaming of the granite.It is recognised that the current name 'Grassy Suite' (e.g. Burrett & Martin, 1989; Blevin & Chappell, 1995) is also invalid because of the priority of Grassy Group, and this will be renamed in the future.Skarns closely adjacent to the Sandblow Granite are developed in calcareous rocks of the Grassy Group and host economically important scheelite deposits at Grassy.|16-MAY-23
74932|Sandblow Granite|References|Black, L.P. , McClenaghan, M.P. , Korsch, R.J. , Everard, J.L. , Foudoulis, C. 2005 Significance of Devonian-Carboniferous igneous activity in Tasmania as derived from U-Pb SHRIMP dating of zircon Australian Journal of Earth Sciences 52 (6) p807-829.Blevin, P.L. , Chappell, B.W. 1995 Chemistry, Origin, and Evolution of Mineralized Granites in the Lachlan Fold Belt, Australia: The Metallogeny of I- and S-Type Granites Economic Geology 90 (6) p1604-1619Burrett, C.F. , Martin, E.L. 1989 Geology and Mineral Resources of Tasmania. Geological Society of Australia. Special Publication 15 574ppChappell, B.W. , English, P.M. , King, P.L. , White, A.J.R. , Wyborn, D. 1991 Granites and related rocks of the Lachlan Fold Belt (1:1 250 000 scale map). Bureau of Mineral Resources, Australia 1v mapKwak, T.A.P. , Tan, T.H. 1981 The geochemistry of zoning in skarn minerals at the King Island(Dolphin) Mine. Economic Geology 76(2) p468-497Large, R.R. 1971 Metasomatism and scheelite mineralization at Bold Head, King Island. AusIMM. Proceedings 238 p31-45Solomon, M. 1981 An introduction to the geology and metallic ore deposits of Tasmania. Economic Geology 76(2) p194-208Wesolowski, D., Cramer, J.J., & Ohmoto, H., 1985: Scheelite mineralisation in skarns adjacent to Devonian granitoids at King Island, Tasmania. In Taylor, R.P. & Strong, D.F., (eds): Recent advances in the Geology of Granite-Related Mineral Deposits.  Can. Inst. Min. Metall. p. 234 ¿ 251.|16-MAY-23
74932|Sandblow Granite|Parent|Grassy Suite.|16-MAY-23
74932|Sandblow Granite|Proposer|C.R. Calver|16-MAY-23
29227|Sarah-Jane Quartzite|Name source|Mt Sarah-Jane [DN550400] Wedge 1:100 000 Mapsheet.|16-MAY-23
29227|Sarah-Jane Quartzite|Type section locality|Approximately 1000 m of white quartzite exposed on strike ridge west of Mt Eliza [DN508425-DN504438].|16-MAY-23
29227|Sarah-Jane Quartzite|Extent|Type section crosses southern outcrop belt extending from Condominium Creek [DN485435] to Whitewater Creek [DN570430]. Northern, lithologically identical outcrop belt extending from Celtic Hill [DN470465] to north of Lake Judd [DN540435] is regarded as a correlate.|16-MAY-23
29227|Sarah-Jane Quartzite|Thickness range|800-1000 m.|16-MAY-23
29227|Sarah-Jane Quartzite|Lithology|White to pale pink, cross-bedded orthoquartzite, with minor interbeds of phyllite.|16-MAY-23
29227|Sarah-Jane Quartzite|Relationships and boundaries|Belongs to Mt Anne Group. Conformably overlies Lake Judd Formation at DN508425 and is conformably overlain by Lonely Tarns Formation at DN548416.|16-MAY-23
29227|Sarah-Jane Quartzite|Age reasons|Late Precambrian, due to tectonometamorphic grade and regional geological setting (see Turner, 1989).|16-MAY-23
29227|Sarah-Jane Quartzite|Proposed publication|Explanatory Report, Department of Mines, Tasmania, for Pedder 1:50 000 Mapsheet|16-MAY-23
16654|Scamander Formation|Name source|Town of Scamander at GDA Zone 55, 605511 mE 5410183 mN in northeast Tasmania.|16-MAY-23
16654|Scamander Formation|Unit history|Probable equivalent of previous units Scamander Slate and Quartzite (defined and described by Walker, 1957 (stratno 75740), Scamander Quartzite and Slate (29256), Scamander Sandstone (31326) and Scamander Siltstone (31325). The Scamander Formation (16654) is shown as formal but not current in ASUD database but has no definition card. This definition card is intended to complete establishment of the Scamander Formation as a replacement/variation of the previous Scamander Slate and Quartzite (now unacceptable due to dual lithological term). Unlikely to be confused with formal Tasmanian igneous units Scamander Tier Granodiorite/Suite as this is a sedimentary unit.|16-MAY-23
16654|Scamander Formation|Constituents|Not subdivided.|16-MAY-23
16654|Scamander Formation|Geomorphic expression|Tends to form linear north-south ridges.|16-MAY-23
16654|Scamander Formation|Type section locality|Traverse westwards along Upper Scamander Rd from 603079 mE 5409201 mN to 602687 mE 5409888 mN also along Skyline Link from 603330 mE 5413749 mN to 603521 mE 5413745 mN.|16-MAY-23
16654|Scamander Formation|Confidential_type_locality|No.|16-MAY-23
16654|Scamander Formation|Description at type locality|Massive quartz-rich sandstones with minor siltstone and mudstone.|16-MAY-23
16654|Scamander Formation|Extent|The Formation extends between the Devonian Granite outcrops around St Helens southwards to the St Marys Porphyrite which unconformably overlies the Formation.|16-MAY-23
16654|Scamander Formation|General description|The dominance of massive sandstones over siltstones and mudstones distinguish the Formation from other Panama Group units to the west. The contact is a west-dipping thrust. Parent unit: Panama Group which is part of the Mathinna Supergroup.|16-MAY-23
16654|Scamander Formation|Thickness range|Up to 3km, based on structural cross-sections within and outside the type area. Thickness variations: unknown.|16-MAY-23
16654|Scamander Formation|Lithology|Abundant medium and thick bedded massive sandstones dominate over subordinate siltstone and grey mudstones. Current related sedimentary structures abundant.|16-MAY-23
16654|Scamander Formation|Depositional environment|Powell et al. (1993) showed that the rocks are proximal marine turbidites and are predominantly C, D channel related lobe transition or overbank facies. They contain abundant sedimentary structures such as cross-lamination, load casts, convolute folds and small scale synsedimentary slump folds.|16-MAY-23
16654|Scamander Formation|Fossils|A Monograptid and various marine invertebrates at localities close to the type area (see Age and Evidence below), vascular plants (Hostimella) away from the type area.|16-MAY-23
16654|Scamander Formation|Relationships and boundaries|Thrust fault contact to the west with adjacent older units of the Panama Group. Intruded by Middle Devonian Scamander Tier Granodiorite within the type area, and unconformably overlain by Middle Devonian extrusive St Marys Porphyry away from the type area.|16-MAY-23
16654|Scamander Formation|Identifying features|Dominance of massive sandstones|16-MAY-23
16654|Scamander Formation|Structure and Metamorphism|Dominant structural trends determined by eastward facing inclined F1 folds with open to tight interlimb angles and low angle north-south plunges. Associated S1 has approximate N-S sub-vertical orientation. Related easterly transport along west dipping thrusts. Post D1 regional anchizonal metamorphism (sub-greenschist facies) (Patison et al. 2001).|16-MAY-23
16654|Scamander Formation|Age reasons|Early Devonian - based on an early Devonian (Pragian) monograptid (Rickards and Banks 1979). The associated fauna includes vascular plants, rugose corals, polyzoans, brachiopods, bivalves and crinoids, a conularid, orthocone cephalopods and abundant dacryoconarids (Rickards and Banks 1979), which also indicate an Early Devonian age.|16-MAY-23
16654|Scamander Formation|Correlations|Correlated by Powell et al. (1993) with the "Sidling sandstone" (now formalised as Sideling Sandstone) west of Scottsdale Batholith.|16-MAY-23
16654|Scamander Formation|Alteration and Mineralisation|There is no current mining activity but the existence of adits and excavations in the forest testify to former exploitation of the tin, copper, lead, zinc, gold and silver of the Scamander Mineral Field (Groves 1972).|16-MAY-23
16654|Scamander Formation|Geophysical Expression|Magnetic lineaments present defining a) probable F1 folds and b) strike slip faults intruded by dolerite dykes (Leaman 2008). Some structural correlations with magnetic worms. Variable radiometric expression.|16-MAY-23
16654|Scamander Formation|Geochemistry|Using the geochemical classification of Herron (1988), the sandstones mostly plot in the Sublitharenite field, the siltstones in the Litharenite field and the mudstones in the Shale field.|16-MAY-23
16654|Scamander Formation|Defn author|Dr Michael Worthing Mineral Resources Tasmania, 23-JUN-2010.|16-MAY-23
16654|Scamander Formation|Proposed publication|Worthing M.A.; Woolward I.R. 2010. Explanatory Report on the 1:25,000 scale digital geological map sheets Dublin Town (5840), Brilliant (5841), Falmouth (6040) and Beaumaris (6041). Mineral Resources Tasmania.|16-MAY-23
16654|Scamander Formation|References|Groves, D.I. 1972. The zoned mineral deposits of the Scamander-St Helens district. Bulletin of the Geological Survey of Tasmania, 53. Tasmanian Department of Mines. **Herron, M.M. 1988. Geochemical Classification of Terrigenous Sands and Shales from Core or Log Data. Journal of Sedimentary Petrology, 58, 820-829. **Leaman, D. 2008 Assessment of Selected Features in the 2007 Magnetic Surveys of North East Tasmania. Report for Mineral Resources Tasmania. Leaman Geophysics. ** Patison, N.L.; Berry, R.F.; Davidson, G.J.; Taylor, B.P.; Bottrill, R.S.; Manzi, B.; Ryba, J.; Shepherd, R.E. 2001. Regional Metamorphism of the Mathinna Group, northeast Tasmania. Australian Journal of Earth Sciences, 48, 281-292. **Powell McA, C.; Baillie, P.W.; Conaghan, P.J.; Turner, N.J.. 1993. The mid Palaeozoic turbiditic Mathinna Group, northeast Tasmania. Australian Journal of Earth Sciences, 40, 169-196.  **Rickards, R.B., Banks, MR. 1979. An early Devonian monograptid from the Mathinna Group, Tasmania. Alcheringa, 3, 307-311.|16-MAY-23
24490|Scotts Peak Road Member|Name source|Scotts Peak Road [DN480480], Wedge 1:100 000 Mapsheet|16-MAY-23
24490|Scotts Peak Road Member|Type section locality|Approximately 200 m of reddish, laminated slate and siltstone exposed in roadcuts along the Scotts Peak Road between DN478486 (base) and DN 479487 (top).|16-MAY-23
24490|Scotts Peak Road Member|Extent|The unit is exposed over about 2 km2 just south of Sandfly Creek.  Lithologic correlates are exposed in two smaller areas to the north. The unit is indicated on the Pedder 1:50 000 geological map by the symbol Psr.|16-MAY-23
24490|Scotts Peak Road Member|Thickness range|Approximately 200 m. |16-MAY-23
24490|Scotts Peak Road Member|Lithology|Pelite (slate or mudstone) with siltstone laminae. Variable but predominantly reddish colour.|16-MAY-23
24490|Scotts Peak Road Member|Relationships and boundaries|Part of Huon River Formation, Pandani Group. At type section, conformably overlies weathered domomitic siltstone of Huon River Formation, and is conformably overlain by weathered pale green slate of Huon River Formation.|16-MAY-23
24490|Scotts Peak Road Member|Age reasons|Late Precambrian (as for Pandani Group).|16-MAY-23
24490|Scotts Peak Road Member|Proposed publication|Explanatory Report, Department of Mines, Tasmania, for Pedder 1:50 000 Mapsheet|16-MAY-23
24490|Scotts Peak Road Member|Proposer|Calver C.R.|16-MAY-23
74594|Shower Droplet Volcanics|Name source|Shower Droplet Rock, East Coast King Island. Grassy 1:25000 map sheet.|16-MAY-23
74594|Shower Droplet Volcanics|Unit history|'Picrite unit' of Waldron & Brown, 1993; 'picritic suite' of Calver & Walter, 2000.|16-MAY-23
74594|Shower Droplet Volcanics|Geomorphic expression|Forms low relief shore platforms with a rugged, undulose character.|16-MAY-23
74594|Shower Droplet Volcanics|Type section locality|Shower Droplet Rock, -39.984S 144.128E.|16-MAY-23
74594|Shower Droplet Volcanics|Description at type locality|The formation at Shower Droplet rock consists of interbedded pillows, thin flows and hyaloclastites with very well-preserved volcanic textures (Scott, 1951; Solomon, 1968). A significant feature of the Shower Droplet Volcanics is the presence of numerous thin flows with distinctive pahoehoe textured tops (Meffre et al., 2004; Direen & Jago, 2008), indicating that at least part of the sequence was erupted subaerially.|16-MAY-23
74594|Shower Droplet Volcanics|Extent|Southeastern quadrant of King Island. This formation is known from just south of Naracoopa, to south of City of Melbourne Bay.|16-MAY-23
74594|Shower Droplet Volcanics|Thickness range|Minimum 300m (Direen & Jago, 2008), total thickness unknown as the contact with the (inferred) overlying Grahams Road Volcanics is not exposed (Meffre et al., 2004).|16-MAY-23
74594|Shower Droplet Volcanics|Lithology|Picrite aa, pillow and pahoehoe lavas, volcaniclastics  and derivative mafic hyaloclastitic sediments.|16-MAY-23
74594|Shower Droplet Volcanics|Depositional environment|Volcanically active basin; both submarine and subaerial extrusion.|16-MAY-23
74594|Shower Droplet Volcanics|Relationships and boundaries|Disconformable with underlying City of Melbourne Volcanics (Meffre et al., 2004). Angular unconformity above Fraser Formation at a basement high near Naracoopa (Direen & Jago, 2008). Faulted contacts with (inferred) overlying Grahams Road Volcanics, dykes of which intrude the Shower Droplet Formation, but not vice versa (Meffre et al., 2004).|16-MAY-23
74594|Shower Droplet Volcanics|Age reasons|Ediacaran. 579±16 Ma, based on a 5 point Sm-Nd isochron (Meffre et al., 2004).|16-MAY-23
74594|Shower Droplet Volcanics|Correlations|Tentatively correlated with picrite volcanic lavas in western Victoria Ozenkadnook Subzone (Crawford, 1997; Direen, 1999; Crawford et al., 2003).|16-MAY-23
74594|Shower Droplet Volcanics|Proposed publication|Meffre, S., Direen, N.G., Crawford, A.J. and Kamenetsky, V., 2004. Mafic volcanics on King Island, Tasmania: evidence for break-up in east Gondwanaland at ca.579 Ma. Precambrian Research, 135, 177-191.|16-MAY-23
74594|Shower Droplet Volcanics|Comments|The Shower Droplet Volcanics is one of the most distinctive formations on King Island, with excellent mesoscale preservation of their original eruptive volcanic textures (Scott, 1951; Solomon, 1968; Direen & Jago, 2008). Texturally, picrite flows, pillows, resedimented mafic hyaloclastites, mafic lapilli tuffs and pillow breccias are all preserved, despite being strongly altered to chlorite, very fine grained quartz and albite, serpentine and magnetite, so that only quenched groundmass clinopyroxene and occasional chromite microphenocrysts and phenocrysts remain unaltered. In thin section, despite the alteration, most rocks have retained primary textures, with abundant small, euhedral, often lantern-shaped, altered olivine phenocrysts set in a fine-grained groundmass of matted, quenched clinopyroxene and altered glass.Whole rock geochemical analyses show the picrites are high in MgO (24-10%) and according to the IUGS (geochemical) classification (Le Bas, 2000), approximately half the Shower Droplet Volcanics. are actually komatiites. However, there has been debate regarding the nomenclature and some studies prefer to use komatiite as a purelytextural term to describe rocks containing spinifex textured olivine. The King Island high Mg rocks do not have spinifex textures so we refer to all the high-Mg rocks as picrites.Geochemically, distinguishing feature of the Shower Droplet Volcanics is their very low TiO2 (0.22¿0.33 wt.%). The Sm¿Nd isotopic ratios are lower than the depleted mantle, suggesting derivation from a plume enrichedmantle. ¿ Nd values of these rocks varies between +3.5 and +4.8 (at 579 Ma) (Meffre et al., 2004).|16-MAY-23
74594|Shower Droplet Volcanics|References|Calver, C.R. and Walter, M.R., 2000. The late Neoproterozoic Grassy Group of King Island, Tasmania: correlation and palaeogeographic significance. Precambrian Research, 100, 299-312.Crawford, A.J., 1997. Appendix 2 Wholerock geochemistry. In: S. Maher, D.H. Moore, A.J. Crawford, R. Twyford and C.M. Fanning (Editors), Test drilling of the southern margin of the Murray Basin. Victorian Initiative for Minerals and Petroleum Report 52. Geological Survey of Victoria, pp. 222-226.Crawford A J, Cayley R A, Taylor D H, Morand V J, Gray C M, Kemp A I S, Wohlt K E, Vandenberg A H M, Moore D H, Maher S, Direen N G, Edwards J, Donaghy A G, Anderson J A & Black L P, 2003, Neoproterozoic and Cambrian continental rifting, continent-arc collision and post-collisional magmatism. In: Birch W D, ed. Geology of Victoria. Geological Society of Australia Special Publication 23: 73-93.Direen, N.G., 1999. Geology and geophysics of the Koonenberry Belt, far western New South Wales, and eastern Australian correlates. Pts 1 & 2. Ph.D Thesis, University of Tasmania, Hobart.Direen, N G, & Jago, J B, 2008, The Cottons Breccia (Ediacaran), and its tectonostratigraphic context within the Grassy Group, King Island, Australia: a rift-related gravity slump deposit. Precambrian Research 165: 1-14Le Bas, M.J., 2000. IUGS reclassification of the high Mg and picritic volcanic rocks. Journal of Petrology 41, 1467¿1470.Meffre, S., Direen, N.G., Crawford, A.J. and Kamenetsky, V., 2004. Mafic volcanics on King Island, Tasmania: evidence for break-up in east Gondwanaland at ca.579 Ma. Precambrian Research, 135, 177-191.Scott, B., 1951. The petrology of the volcanic rocks of south east King Island, Tasmania. Papers and Proceedings of the Royal Society of Tasmania, 1950: 113¿141.Solomon, M., 1968. The nature and possible origin of the pillow lavas and hyaloclastite breccias of King Island. Quarterly Journal of the Geological Society (London), 124: 153¿169.|16-MAY-23
74594|Shower Droplet Volcanics|Parent|Skipworth Subgroup, Grassy Group.|16-MAY-23
74594|Shower Droplet Volcanics|Proposer|N G Direen.|16-MAY-23
75362|Sideling Sandstone|Name source|The Sideling Range GDA94 Zone 55, 535310 mE, 5435180 mN, 11 kilometres south-west of Scottsdale in northeast Tasmania.|16-MAY-23
75362|Sideling Sandstone|Unit history|Replacement of Sidling Sandstone which was accidently formalised and mis-spelled and also replaces the informal Sidling sandstone. Previous database entry (Strat No 34172) identifying Sidling Sandstone as a formal unit was in error and based on a few erroneous uses in figures in a publication by A.R. Reed, in which most uses in the body of the text were the correct, informal 'Sidling sandstone'.|16-MAY-23
75362|Sideling Sandstone|Constituents|Not subdivided.|16-MAY-23
75362|Sideling Sandstone|Geomorphic expression|Undulating, elevated to hilly ground which is similar to that of the adjacent unit.|16-MAY-23
75362|Sideling Sandstone|Type section locality|Traverse along the Tasman Highway between points  535610 mE, 5431680 mN and 536310 mE, 5434683 mN (GDA94, zone 55) where the highway crosses the Sideling Range about 15 kilometres southwest of Scottsdale in northeast Tasmania. See 1:25,000 topographic map series, sheet 5243: LISLE, and Mineral Resources Tasmania digital geology equivalent.|16-MAY-23
75362|Sideling Sandstone|Confidential_type_locality|No.|16-MAY-23
75362|Sideling Sandstone|Description at type locality|Massive fine-grained, tightly folded pale-grey sandstone beds with minor interbeds of siltstone, as prominent roadside outcrops.|16-MAY-23
75362|Sideling Sandstone|Extent|The formation extends to the north adjacent to the Sottsdale Batholith as far as the coast near Bridport and also for about 5 Km southeast of the type locality on the Tasman Highway.|16-MAY-23
75362|Sideling Sandstone|General description|The dominance of fine-grained sandstone over siltstone has been used to distinguish the formation from the underlying Lone Star Siltstone. Parent unit: Panama Group which is part of the Mathinna Supergroup.|16-MAY-23
75362|Sideling Sandstone|Thickness range|At least 1,500 m (top not exposed). Unknown variations in thickness.|16-MAY-23
75362|Sideling Sandstone|Lithology|Dominantly turbiditic, fine- and very fine-grained sandstone with interbedded siltstone.|16-MAY-23
75362|Sideling Sandstone|Depositional environment|Marine, probably largely deposited in one or more sandy submarine fan complexes. Based on geochemical classification the formation was deposited in a passive margin tectonic setting (Roser and Korsch, 1986) and had a quartzose sedimetary provenance (Roser and Korsch, 1988).|16-MAY-23
75362|Sideling Sandstone|Fossils| Contains Early Devonian plant remains.|16-MAY-23
75362|Sideling Sandstone|Diastems or hiatuses|None Known.|16-MAY-23
75362|Sideling Sandstone|Relationships and boundaries|The unit has a conformable transitional contact with the underlying Lone Star Siltstone. Top is not exposed. In map view the unit is bound to the east by an intrusive contact with the Diddleum Granodiorite (of the Scottsdale Batholith).|16-MAY-23
75362|Sideling Sandstone|Identifying features|The dominance of fine-grained sandstone over siltstone distinguishes the formation from the underlying Lone Star Siltstone|16-MAY-23
75362|Sideling Sandstone|Structure and Metamorphism|Structural style is upright to steeply inclined, generally open to close folds with an axial planar penetrative slaty cleavage in the finer-grained lithologies. Metamorphism is anchizonal (200-300°C, sub-greenschist facies) according to Patison et al. (2001), with hornblende hornfels facies adjacent to the Scottsdale Batholith|16-MAY-23
75362|Sideling Sandstone|Age reasons|Early Devonian based on containing plant fossils of that age (Cookson 1937; Banks 1962), being intruded by middle Devonian granodiorite of the Scottsdale Batholith, and overlying the Lone Star Siltstone which contains late Silurian (Ludlow) graptolites.|16-MAY-23
75362|Sideling Sandstone|Correlations|Uncertain correlation with sandstone dominated sequences to the east of the Scottsdale Batholith.|16-MAY-23
75362|Sideling Sandstone|Alteration and Mineralisation|None.|16-MAY-23
75362|Sideling Sandstone|Geophysical Expression|Variable expression at intermediate intensity of all three channels on K-Th-U RGB images of airborne radiometric data|16-MAY-23
75362|Sideling Sandstone|Geochemistry|Using the geochemical classification of Herron (1988) the sandstones are litharenite and the siltstones are wacke or shale.|16-MAY-23
75362|Sideling Sandstone|Defn author|Dr Marcus McClenaghan Mineral Resources Tasmania, 04-FEB-2010|16-MAY-23
75362|Sideling Sandstone|Proposed publication|Seymour, D. B.; Woolward, I. R.; McClenaghan, M. P. 2010. Stratigraphic revision and re-mapping of the Mathinna Supergroup west of the Scottsdale Batholith, Northeast Tasmania (Explanatory Report for parts of 1:25 000 scale map sheets Low Head, Tam O'Shanter, Weymouth, Retreat, Lilydale, Bridport, Bowood, Nabowla, Lisle and Patersonia). Mineral Resources Tasmania, 1:25 000 Scale Digital Geological Map Series Explanatory Report 4.; possibly also AJES.|16-MAY-23
75362|Sideling Sandstone|References|Herron M. M., 1988. Geochemical classification of terrigenous sands and shales from core or log data. Journal of Sedimentary Petrology, 58, 820-829. **Patison, N. L.; Berry, R. F.; Davidson, G. J.; Taylor, B. P.; Bottrill, R. S.; Manzi, B.; Ryba, J.; Shepherd, R. E. 2001. Regional metamorphism of the Mathinna Group, northeast Tasmania. Australian Journal of Earth Sciences, 48, 281-292. [RefID 23167] **Roser B. P. and Korsch R. J., 1986. Determination of tectonic setting of sandstone-mudstone suites using SiO2 content and K2O/Na2O ratio. The Journal of Geology, 94, 635-650.  **Roser B. P. and Korsch R. J., 1988. Provenance signatures of sandstone-mudstone suites determined using discriminant function analysis of major-element data. Chemical Geology, 67, 119-139.|16-MAY-23
24508|Strickland Gorge Formation|Name source|The Strickland Gorge Formation is named after the gorge of the Fad River (EQ547050) where the upper 26m is almost completely exposed.|16-MAY-23
24508|Strickland Gorge Formation|Type section locality|The type section is designated at an unnamed creek, between EQ596019 and EQ591019, where both the base and the top of the formation is exposed and the total thickness is about 60m.|16-MAY-23
24508|Strickland Gorge Formation|Extent|At present the formation is known from the northern and eastern flanks of Ben Lomond, as far east as Englishtown (EQ440012), as far west as Tower Hill (EQ690024) and as far south as Mistletoe Creek (EP635900) and Mt. Christie (EP578780). It thins and disappears to the east and south, where the Aberfoyle Formation or younger units rest on Mathinna Beds (Calver, ibid).|16-MAY-23
24508|Strickland Gorge Formation|Lithology|The conglomerate layers which are courser-grained and thicker in the lower part of the formation, comprise sub rounded to angular, boulder, cobble and pebble sized class of quartzite, sandstone, siltstone, phyllite, mica schist and quartz in a matrix of grey siltstone or poorly sorted brown sandstone.  They are usually thickly, unevenly and poorly bedded, but in places graded bedding is present.  The siltstone is light to dark grey, medium to think bedded, slightly micaceous, sometimes calcareous and contains rare to abundant drop stones, often occurring in clumps.  It usually has irregular, lenticular fracture, and is often bioturbated, particularly in the upper part of the formation.  The boundary with the Aberfoyle Formation is placed at the first appearance of the fissile, thinly bedded, fine-grained quartz sandstone and dark carboneous and micaceous siltstone.|16-MAY-23
24508|Strickland Gorge Formation|Fossils|The Strickland Gorge Formation is sparsely to sometimes richly fossiliferous, with a biocoeotic assemblage including brachiopods, bivalves, steroponids and ferestellids.|16-MAY-23
24508|Strickland Gorge Formation|Relationships and boundaries|The Strickland George Formation, belonging to the lower glacio-marine part of the Parmeener Super-group in north eastern Tasmania, consists of interbedded siltstone and conglomerate unconformably overlying Mathinna Beds and conformably overlain by the Aberfoyle Formation (A.H. Blissett, 1959, Bull. Geol. Surv. Tasm. 46). The boundary with the Aberfoyle Formation is placed at the first apperance of the fissile, thinly bedded, fine-grained quartz sandstone and dark carboneous and micaceous siltstone.|16-MAY-23
24508|Strickland Gorge Formation|Age reasons|Preliminary palynological and palaeontological evidence (Trigonotreta stokesii, Ecrydesma ?cordatum) and the relationship with the Aberfoyle Formation suggests a Tamarian (Permian) age.|16-MAY-23
24508|Strickland Gorge Formation|Proposed publication|Calver C.R., Everard J.L., Findlay R.H. & Lennox P.G., 1988. Geological atlas 1:50 000 series Sheet 48 (8414N), Ben Lomond, Department of Mines, Tasmania.  ALSO: same authors. In prep. Explanatory Report (for above map).|16-MAY-23
24509|Styx Dolomite|Name source|Styx River [DN590600], Wedge 1:100 000 Mapsheet.|16-MAY-23
24509|Styx Dolomite|Type section locality|Outcrop along the Weld River [DN554578-DN548581] constitute the type area.|16-MAY-23
24509|Styx Dolomite|Extent|Unit is exposed over approximately 2 km2 in the headwaters of the Weld River. |16-MAY-23
24509|Styx Dolomite|Thickness range|Approximately 500 m; uncertain due to faulting.|16-MAY-23
24509|Styx Dolomite|Lithology|Massive, pale grey dolomite; rare red mudstone.|16-MAY-23
24509|Styx Dolomite|Relationships and boundaries|Overlies, probably conformably, the Devils Eye Dolomite at DN554578 (contact not exposed); top of unit is faulted out.|16-MAY-23
24509|Styx Dolomite|Age reasons|Late Precambrian (as for Weld River Group).|16-MAY-23
24509|Styx Dolomite|Proposed publication|Pap. Proc. R. Soc. Tasm., 123|16-MAY-23
75979|Tebrakunna Dolerite|Name source|Tebrakunna Road, in the type area.|16-MAY-23
75979|Tebrakunna Dolerite|Geomorphic expression|Usually in-weathering relative to granite host rocks in coastal outcrops; may form narrow slots or gulches in foreshore outcrops. The dykes crop out poorly inland, with subdued geomorphic contrast. Abundant rounded boulders of dolerite float may contrast with angular Mathinna Supergroup float.|16-MAY-23
75979|Tebrakunna Dolerite|Type section locality|Defined as those dolerite dykes cropping out between a point ~3 km E of Gardens Lagoon (~41deg 09'S 148 deg 14' E) and Old Chum Dam (~41 deg 04' S 148 deg 03' E), northeast Tasmania. The designated type locality is a large dyke cropping out near the bridge on Tebrakunna Road over the Great Musselroe River (~41 deg 05' 17" S 148 deg 03' 39" E)(McClenaghan M. P. & Williams P. R. 1983).|16-MAY-23
75979|Tebrakunna Dolerite|Description at type locality|At least twenty subparallel, NE- to NNE-trending, +/- vertical dolerite dykes, 1 - 30 m thick, forming a swarm ~ 17 km wide.|16-MAY-23
75979|Tebrakunna Dolerite|Extent|The dyke swarm extends NE to the Mt William area and SW at least as far as the Pyengana area. Geophysical evidence suggests a dolerite dyke at Roses Tier is an extension of the swarm.|16-MAY-23
75979|Tebrakunna Dolerite|General description|Similar dolerite dykes at South Maria Island, Freycinet Peninsula (Everard 2001), Friendly Beaches, Bicheno, St Helens, Boobyalla and on the Furneaux Islands (extending north to Hogan Island) may be outliers of the swarm; these are more variable in orientation.|16-MAY-23
75979|Tebrakunna Dolerite|Lithology|Dark grey, fine- to medium-grained (mean grain size 0.5 - 2 mm), aphyric to sparsely plagioclase-phyric dolerite, with primary plagioclase, augite or titaniferous augite, olivine (?), ilmenite and magnetite.|16-MAY-23
75979|Tebrakunna Dolerite|Relationships and boundaries|The dykes intrude Devonian granite plutons (including Gardens Granodiorite, Pyengana Granodiorite, Poimena Granite, Ansons Bay Granite, Lottah Granite)  and the Mathinna Supergroup. Usually straight to undulose, sharp contacts with chilled margins; rarely irregular diffuse contacts with indications of assimilation or magma mixing with host granite.|16-MAY-23
75979|Tebrakunna Dolerite|Identifying features|Distinguished from Jurassic dolerite by form, metamorphism and geochemistry.|16-MAY-23
75979|Tebrakunna Dolerite|Structure and Metamorphism|Unfoliated. Primary minerals are usually partly replaced by greenschist facies assemblages (including actinolite, chlorite, sericite, epidote, biotite, titanite, calcite).|16-MAY-23
75979|Tebrakunna Dolerite|Age reasons|Early Carboniferous dates of 330 +/- 6 Ma (K/Ar, dyke SW of Ansons Bay) and 334 +/- 7 Ma (40Ar/39Ar plateau, dyke near Mt William area) are considered minimum ages (McClenaghan et al, in prep. D. Phillips analyst).  A Late Devonian maximum age is constrained by the youngest known country rock, the Lottah Granite  (377.8 +/-2.4 Ma; U-Pb SHRIMP on zircon, Black et al. 2005)|16-MAY-23
75979|Tebrakunna Dolerite|Alteration and Mineralisation|Minor pyrite sometimes present.|16-MAY-23
75979|Tebrakunna Dolerite|Geophysical Expression|Magnetic susceptibility highly variable (0.5 - 40 x 10-3 SI), but usually higher than country rocks. Usually associated with weak to moderate linear anomalies on aeromagnetic images.|16-MAY-23
75979|Tebrakunna Dolerite|Geochemistry|Uncontaminated dykes have the composition of tholeiitic to weakly alkali basalt (SiO2 46-52%) with tholeiitic fractionation trends. Other dykes are broadly andesitic (SiO2 52 - 62%), with petrographic evidence for assimilation of host granite.|16-MAY-23
75979|Tebrakunna Dolerite|References|BLACK L. P., MCCLENAGHAN M. P., KORSCH R. J., EVERARD J. L. & FOUDOULIS C. 2005. The significance of Devonian-Carboniferous igneous activity in Tasmania, as derived from U-Pb SHRIMP dating of zircon. Australian Journal of Earth Sciences 52, 807-829.  **EVERARD J.L. 2001. Intrusive relationships of granite and dolerite at Lagunta Creek, Freycinet Peninsula. Papers and Proceedings of the Royal Society of Tasmania 135, 63-74.  **MCCLENAGHAN M. P. & WILLIAMS P. R. 1983. Geological Atlas 1:50 000 series. Sheet 33 (8515N). Blue Tier. Tasmania Department of Mines.  **MCCLENAGHAN M. P.  1984. The petrology, mineralogy and geochemistry of the Pyengana and Gardens granodiorites, the Hogans Road diorite and the dolerite dykes of the Blue Tier Batholith. Tasmania Department of Mines Unpublished Report 1984/04.  **MCCLENAGHAN M. P., PHILLIPS D. & EVERARD J. L. 2011. Dolerite dykes of eastern Tasmania. Tasmanian Geological Survey Report, in prep.|16-MAY-23
36813|Tippogoree Group|Name source|After the locality Tippogoree and the Tippogoree Hills (496300mE, 5446300mN).|16-MAY-23
36813|Tippogoree Group|Constituents|Stony Head Sandstone and Turquoise Bluff Slate (Powell et al., 1993).|16-MAY-23
36813|Tippogoree Group|Type section locality|None specified, but typical outcrops of Stony Head Sandstone occur on the Bridport to Georgetown road between about 496400mE, 5448500mN and 508600mE, 5451400mN (Australian Map Grid; AUS66; 55G). Typical outcrops of Turquoise Bluff Slate are exposed at the Australasian Slate Quarry at 504600mE, 5456500mN.|16-MAY-23
36813|Tippogoree Group|Extent|Pre-Devonian sedimentary rocks cropping out east of the Tamar River and west of Pipers River where it crosses the Bridport to Georgetown road at 508600mE, 5451400mN (Australian Map Grid; AUS66; 55G).|16-MAY-23
36813|Tippogoree Group|Thickness range|Unknown, but estimates by Powell et al. (1993) of the thickness of the Stony Head Sandstone and Turquoise Bluff Slate indicate a thickness of greater than 2km.|16-MAY-23
36813|Tippogoree Group|Lithology|Thick graded beds of fine- to medium-, rarely coarse-grained sandstone and minor pelite stratigraphically overlain by a predominantly massive but rarely bioturbated black slate  (Powell et al., 1993).|16-MAY-23
36813|Tippogoree Group|Fossils|Two poorly preserved graptolites of Early to Middle Ordovician (Bendigonian Be1 to Darriwillian Da3) age (Banks & Smith, 1968; VandenBerg pers comm.) are contained within the Turquoise Bluff Slate.|16-MAY-23
36813|Tippogoree Group|Relationships and boundaries|No base is known. The top of the unit is not exposed but is characterised by a change from strongly cleaved and recumbently folded Turquoise Bluff Slate to open upright folded classical turbidites of the Bellingham Formation (Panama Group).|16-MAY-23
36813|Tippogoree Group|Age reasons|Two poorly preserved graptolites of Early to Middle Ordovician (Bendigonian Be1 to Darriwillian Da3) age (Banks & Smith, 1968; VandenBerg pers comm.) are contained within the Turquoise Bluff Slate. The unit is overlain by classical turbidites of the Panama Group which contain vascular plant remains of Devonian age (Banks, 1962).|16-MAY-23
36813|Tippogoree Group|References|*BANKS, M. 1962. The Silurian and Devonian Systems. Journal of the Geological Society of Australia 9, 177-188.     *97/28855 - BANKS, M. & SMITH A. 1968. A graptolite from the Mathinna Beds, northeastern Tasmania. Australian Journal of Science 31, 118-119.     *94/27811 - POWELL, C. McA., BAILLIE,  P.W., CONAGHAN, P. J. & TURNER, N. J. 1993. The mid-Palaeozoic turbiditic Mathinna Group, NE Tasmania. Australian Journal of Earth Sciences 40, 169-198.|16-MAY-23
24543|Twin Creeks Formation|Name source|Twin Creeks [DN483414], Wedge 1:100 000 Mapsheet.|16-MAY-23
24543|Twin Creeks Formation|Type section locality|Presently known outcrop area (bounded by DN483414-480390-500390-500410-490420) is the designated type area. The unit is well-exposed along the Scotts Peak Road between DN483414-480390.|16-MAY-23
24543|Twin Creeks Formation|Extent|The unit is exposed over about 6 km2 east of Edgar Bay in the southeastern part of the Wedge 1:100 000 mapsheet.|16-MAY-23
24543|Twin Creeks Formation|Thickness range|Approximately 1 km.|16-MAY-23
24543|Twin Creeks Formation|Lithology|Predominantly phyllite, with lesser dolomite and quartz siltstone and rare orthoquartzite.|16-MAY-23
24543|Twin Creeks Formation|Relationships and boundaries|Considered to be the oldest unit of the Mt Anne Group. The base is obscured by Quaternary cover. The unit dips and faces towards the Lake Judd Formation but the contact is not exposed and is probably faulted.|16-MAY-23
24543|Twin Creeks Formation|Age reasons|Late Precambrian, due to tectonometamorphic grade and regional geological setting (see Turner, 1989).|16-MAY-23
24543|Twin Creeks Formation|Proposed publication|Explanatory Report, Department of Mines, Tasmania: Pedder 1:50 000 Sheet|16-MAY-23
81676|Victory Springs Formation|Name source|Victory Springs (370420mE, 5440685mN)(Zone 55G, GDA94)|16-MAY-23
81676|Victory Springs Formation|Unit history|Keith River gossan zone (in part).|16-MAY-23
81676|Victory Springs Formation|Geomorphic expression|Karst is developed in magnesite-dominant intervals, mainly in the Lyons River and Central Creek. Features include solutional notches, surface runnels, ridges, pinnacles and slots, a collapsed boulder cave and underground drainage (Sharples 1997). The remainder of the unit has limited topographic contrast with adjacent units.|16-MAY-23
81676|Victory Springs Formation|Type section locality|The type section is specified as exposures in the Lyons River between (~366125mE, 5435000mN) and (365940mE/5435970mN), accessible from the end of Farquhars Road.|16-MAY-23
81676|Victory Springs Formation|Extent|A linear, NE-SW oriented partly fault-bounded block ~12km long and up to 900m wide, extending from near Victory Springs to the middle-upper Lyons River area (~363110mE, 5431100mN). Concealed by Cainozoic basalt to the SW. Terminated to the NE by a faulted contact with Wynyard Tillite.|16-MAY-23
81676|Victory Springs Formation|Thickness range|900m (apparent) at type section. The true stratigraphic thickness is difficult to estimate due to internal structural complexity and truncation of the unit by faulting. Thickness variations unknown due to internal structural complexity.|16-MAY-23
81676|Victory Springs Formation|Lithology|Dominantly mudstone, phyllitic mudstone, siltstone, quartzite, carbonate (dolomite and magnesite), minor quartz-mica schists and rare amphibolite, with intervals of hematite-limonite-pyrite gossan.|16-MAY-23
81676|Victory Springs Formation|Depositional environment|Protolith probably shallow marine sediments.|16-MAY-23
81676|Victory Springs Formation|Fossils|Not known.|16-MAY-23
81676|Victory Springs Formation|Diastems or hiatuses|Not known.|16-MAY-23
81676|Victory Springs Formation|Relationships and boundaries|Overlies the Keith Schist, possibly conformably; faulted against Permo-Carboniferous strata (Inglis Siltstone) to the northwest.|16-MAY-23
81676|Victory Springs Formation|Identifying features|Low metamorphic grade and the presence of carbonate distinguishes the unit from the Keith Schist.|16-MAY-23
81676|Victory Springs Formation|Structure and Metamorphism|High strain, multiply deformed (F1/F2 and F3 folds), mostly low to very low metamorphic grade.|16-MAY-23
81676|Victory Springs Formation|Age reasons|Neoproterozoic, probably Tonian. Youngest concordant detrital zircon grain 874 +/-11 Ma (from n=91; LA-ICPMS; Mulder et al. in prep.)|16-MAY-23
81676|Victory Springs Formation|Correlations|Possible correlate of the Bowry Formation.	|16-MAY-23
81676|Victory Springs Formation|Alteration and Mineralisation|Hosts the Victory Copper Mine (Waller 1901; McNeil 1961), several copper-iron prospects in the Keith River Gossan Zone, and potentially economically significant magnesite deposits.|16-MAY-23
81676|Victory Springs Formation|Geophysical Expression|Magnetics: coincides with a strong NE-trending linear anomaly; surface samples not notably magnetic. Radiometrics: Patchy response due to poorly exposure, but generally lower counts than adjacent units (Keith Schist, Inglis Siltstone, Cainozoic basalt).|16-MAY-23
81676|Victory Springs Formation|Geochemistry|Limited data apart from magnesite units and gossans; otherwise probably pelitic to psammitic.|16-MAY-23
81676|Victory Springs Formation|Defn author|Everard, J.L. 16-SEP-2019|16-MAY-23
81676|Victory Springs Formation|Comments|Corresponds to units Pam, Pamd and Pamg on Trowutta 1:50000 map sheet (Everard et al. 1996).Corresponds to units Pacm, Pacmd, Pacmg on Keith 1:25000 map sheet (Cumming & Jackman 2018) and Folly 1:25000 map sheet (Seymour & Everard 1998).|16-MAY-23
81676|Victory Springs Formation|References|CUMMING G. V. & JACKMAN C.J. 2018. Digital Geological Atlas 1:25000 series. Sheet 3643. Keith. Mineral Resources Tasmania.  **EVERARD J. L., SEYMOUR D. B. & BROWN A. V. 1996. Geological Atlas 1:50,000 Series, Sheet 27 (7915N). Trowutta. Mineral Resources Tasmania.  **MCNEILL R.D. 1961. Geological reconnaissance of part of the Arthur River area. Tasmania Department of Mines Technical Reports 5, p. 46-60.  **MULDER  J. A & EVERARD J.L., CUMMING G.V., MEFFRE S., BOTTRILL R.S., MERDITH A.S., HALPIN J.A. MCNEILL A, & CAWOOD P.A. Neoproterozoic opening of the Pacific Ocean recorded by multi-stage rifting in Tasmania. Submitted to Earth Science Reviews.  **SEYMOUR D. B. & EVERARD J.L. 1998. Digital Geological Atlas 1:25000 series. Sheet 3644. Folly. Mineral Resources Tasmania.  **SHARPLES, C. 1997. Karst geomorphology and values of the Tarkine. Report to the Australian Heritage Commission & the Tasmanian Conservation Trust, Inc.  **WALLER G.A. 1901. Report on the recent discovery of cannel coal in the parish of Preolenna, and upon the New Victory Copper Mine near the Arthur River. Report of the Secretary of Mines, Tasmania, 1901-1902.|16-MAY-23
24566|Weld River Group|Name source|Weld River [DN570510], Wedge 1:100 000 Mapsheet.|16-MAY-23
24566|Weld River Group|Constituents|Annakananda Formation, Lake Timk Formation, Gomorrah Dolomite, Devils Eye Dolomite, Styx Dolomite, Cotcase Creek Formation.|16-MAY-23
24566|Weld River Group|Extent|The unit is exposed over approximately 100 km2 in the upper Weld River catchment; and smaller areas occur in the upper Styx R. and South Styx R. valleys.|16-MAY-23
24566|Weld River Group|Thickness range|Approximately 5 km (but uncertain due to faulting).|16-MAY-23
24566|Weld River Group|Lithology|Predominantly dolomite.|16-MAY-23
24566|Weld River Group|Relationships and boundaries|Unconformably overlies Precambrian Pandani Group west of Weld River; paraconformably overlies unnamed Precambrian sequence east of Weld River. Weld R. Gp. Is overlain by, with inferred unconformity, by a lithicwacke sequence of probable Middle or Upper Cambarian age (Calver, in press).|16-MAY-23
24566|Weld River Group|Age reasons|Late Precambrian. The unit lacks fossils other than simple algal remains (catagraphs, oolites).|16-MAY-23
24566|Weld River Group|Proposed publication|Pap. Proc. R. Soc. Tasm., 123|16-MAY-23
24566|Weld River Group|References|90/26830|16-MAY-23
24587|Wurawina Supergroup|Name source|Definition:  The term "Wurawina Supergroup" is proposed for a unit in western Tasmania comprising the Denison Group (Late Cambrian and Early Ordovician) below, the Gordon Group and the Eldon Group or Tiger Range Group (Silurian and Early Devonian) above, bounded basally by an unconformity, and overlain with angular unconformity by the Parmeener Supergroup of Late Carboniferous to Triassic age.                                                                                                                                                                                     Derivation: Wurawina is the name of a lake in the Denison Range in south-central Tasmania. Its geographic co-ordinates are 146o16'43"E, 42o32'24"S (Australian Map Grid Zone 55 DN408901). It lies in an area dominated by units of the Supergroup.|16-MAY-23
24587|Wurawina Supergroup|Proposed publication|Pap. Proc. R. Soc. Tasm. Vol. 120, 1986 (accepted)|16-MAY-23
24587|Wurawina Supergroup|Name first published by|Banks M.R., Williams E., 1986|16-MAY-23
24587|Wurawina Supergroup|Proposer|Banks M.R., Williams E.|16-MAY-23
74646|Yarra Creek Shale|Name source|Yarra Creek, which debouches into City of Melbourne Bay. Grassy 1:25000 map sheet.|16-MAY-23
74646|Yarra Creek Shale|Unit history|None known. 'Shale' of Calver & Walter (2000).|16-MAY-23
74646|Yarra Creek Shale|Geomorphic expression|Forms elongate / tabular, grey-red/brown-black outcrops in the shore platform around City of Melbourne Bay.|16-MAY-23
74646|Yarra Creek Shale|Type section locality|Sections on northern and southern shores  of City of Melbourne Bay; 40.010S, 144.113E.|16-MAY-23
74646|Yarra Creek Shale|Description at type locality|Purple, red, gray, buff and brown, planar laminated shale, and minor interbedded volcaniclastic sandstone, dipping moderately (45 degrees) SE (Calver & Walter, 2000). Black shale beds in the middle part of this unit are fossil benthic microbial mats (Calver & Walter, 2000).  The formation here is roughly 150 m thick (thickness uncertain because of incomplete exposure and the presence of andesitic and basaltic intrusives of uncertain extent).  The unit also contains interbedded grey-green tuffs, lavas, and pyritic shale layers (Solomon, 1968; Jago, 1974; Calver & Walter, 2000; Direen & Jago, 2008).|16-MAY-23
74646|Yarra Creek Shale|Extent|Southeastern quadrant of King Island. This formation is well exposed around City of Melbourne Bay where it thickens to the SW (Direen & Jago, 2008).|16-MAY-23
74646|Yarra Creek Shale|Thickness range|Variable, between 3 and 150 m (Direen & Jago, 2008; Calver et al., 2004; Calver & Walter, 2000). Thickness is controlled by extensional faults, and generally thins to NE, away from the type area.|16-MAY-23
74646|Yarra Creek Shale|Lithology|Planar laminated shale, mudstone, peperite (intermingled with overlying City of Melbourne Volcanics basalts).|16-MAY-23
74646|Yarra Creek Shale|Depositional environment|Actively extending, volcanic basin (Direen & Jago, 2008).|16-MAY-23
74646|Yarra Creek Shale|Fossils|Undated /unascribed microbial mats (Calver et al., 2004).|16-MAY-23
74646|Yarra Creek Shale|Diastems or hiatuses|None recognised. Possibility of an undocumented hiatus (Calver et al., 2004).|16-MAY-23
74646|Yarra Creek Shale|Relationships and boundaries|Transitional with the limestone-shale facies of the underlying Cumberland Creek Dolostone (Direen & Jago, 2008). Peperitic / interfingering contact with the overlying City of Melbourne Volcanics (Meffre et al., 2004; Calver et al., 2004; Direen & Jago, 2004). Intruded by sills of the Grimes Intrusive Suite (Meffre et al., 2004, Calver et al., 2004).|16-MAY-23
74646|Yarra Creek Shale|Age reasons|Ediacaran inferred age. Slightly older than 575± 3 Ma, the age of the Grimes Intrusive Suite, which intruded it while it was at least partly lithified (Calver et al., 2004); the uppermost part is equivalent in age to penecontemporaneous City of Melbourne Volcanics with which it interfingers, and which were erupted ca. 579 ± 16 Ma (Meffre et al., 2004).|16-MAY-23
74646|Yarra Creek Shale|Correlations|Correlation with the lower part of the Brachina Formation, South Australia, has been proposed (Calver & Walter, 2000).  May also correlate with the thin (10 m) unnamed red mudstone in the Smithton Trough between the Croles Hill Diamictite and the Spinks Creek Volcanics (part of the Kanunnah Subgroup, northwest Tasmania) (Calver et al., 2004).|16-MAY-23
74646|Yarra Creek Shale|Proposed publication|Calver, C.R., Black, L.P., Everard, J.L. and Seymour, D.B., 2004. U-Pb zircon age constraints on late Neoproterozoic glaciation in Tasmania. Geology, 32(10): 892-896.|16-MAY-23
74646|Yarra Creek Shale|Comments|The predominant lithology (weakly laminated to massive, pale grey-green to red mudstone) is distinct from the enclosing succession.  At the top of the formation, peperitic facies are very distinctive, including lava rafts, gas-charged bubbly sediment/magma mixtures, micro pillows etc. (Calver et al., 2004; Meffre et al., 2004; Direen & Jago, 2008).|16-MAY-23
74646|Yarra Creek Shale|References|Calver, C.R. and Walter, M.R., 2000. The late Neoproterozoic Grassy Group of King Island, Tasmania: correlation and palaeogeographic significance. Precambrian Research, 100, 299-312.Calver, C.R., Black, L.P., Everard, J.L. and Seymour, D.B., 2004. U-Pb zircon age constraints on late Neoproterozoic glaciation in Tasmania. Geology, 32(10): 892-896.Direen, N.G., 1999. Geology and geophysics of the Koonenberry Belt, far western New South Wales, and eastern Australian correlates. Pts 1 & 2. Ph.D Thesis, University of Tasmania, Hobart.Direen, N.G. and Jago, J.B., 2008. The Cottons Breccia (Ediacaran) and its tectonostratigraphic context within the Grassy Group, King Island, Australia: A rift-related gravity slump deposit. Precambrian Research, 165: 1-14.Jago, J.B., 1974. The origin of Cottons Breccia, King Island, Tasmania. Transactions of the Royal Society of South Australia, 98(1): 13-28.Meffre, S., Direen, N.G., Crawford, A.J. and Kamenetsky, V., 2004. Mafic volcanics on King Island, Tasmania: evidence for break-up in east Gondwanaland at ca.579 Ma. Precambrian Research, 135, 177-191.Solomon, M., 1968. The nature and possible origin of the pillow lavas and hyaloclastite breccias of King Island. Quarterly Journal of the Geological Society (London), 124: 153¿169.|16-MAY-23
74646|Yarra Creek Shale|Parent|Grassy Group.|16-MAY-23
74646|Yarra Creek Shale|Proposer|C R Calver & N G Direen|16-MAY-23
75365|Yarrow Creek Mudstone|Name source| Yarrow Creek headwaters: GDA94 Zone 55, 510905 mE, 5452175 mN|16-MAY-23
75365|Yarrow Creek Mudstone|Unit history|Along with the Retreat Formation and Lone Star Siltstone, replaces the Bellingham Formation (Strat No. 1426, of the former Mathinna Group)|16-MAY-23
75365|Yarrow Creek Mudstone|Constituents|None.|16-MAY-23
75365|Yarrow Creek Mudstone|Geomorphic expression|Subdued but undulating topography|16-MAY-23
75365|Yarrow Creek Mudstone|Type section locality|A 1,350m long traverse of Lewis Road between points 511320 mE, 5444235 mN and 511990 mE, 5444945 mN (GDA94 Zone 55). See 1:25,000 topographic map series, sheet 5044: RETREAT, and Mineral Resources Tasmania digital geology equivalent.|16-MAY-23
75365|Yarrow Creek Mudstone|Confidential_type_locality|No.|16-MAY-23
75365|Yarrow Creek Mudstone|Description at type locality|Dominantly thin-bedded mudstone, with subordinate cross-laminated siltstone. Thickness: Approximately 900 m (but base is probably faulted).|16-MAY-23
75365|Yarrow Creek Mudstone|Extent|Currently mapped geographic extent comprises a more or less continuous 0.5 - 4 km wide outcrop belt exending from Weymouth on the Bass Strait coast in the north, some 27 km in (folded) strike length to 2 km north of Bangor in the south.|16-MAY-23
75365|Yarrow Creek Mudstone|General description|Panama Group (of the Mathinna Supergroup).|16-MAY-23
75365|Yarrow Creek Mudstone|Thickness range|Variations are probably largely due to (inferred) faulted lower contact. Calculated or estimated minimum thicknesses vary from about 380 m to about 1015 m (about 900 m at type section).|16-MAY-23
75365|Yarrow Creek Mudstone|Lithology|Thin bedded clastic sedimentary sequence, bed thickness < 30cm. Dominant lithology is cleaved grey mudstone, with subordinate to minor pale-weathering beds of quartz-rich siltstone to very fine-grained sandstone, commonly cross-laminated, and occasional beds of fine-grained quartz-rich sandstone. Ratio of grey mudstone : quartz-rich siltstone + sandstone is ~ 2.7:1|16-MAY-23
75365|Yarrow Creek Mudstone|Depositional environment|Deep marine, distal turbidite-influenced.|16-MAY-23
75365|Yarrow Creek Mudstone|Fossils|None.|16-MAY-23
75365|Yarrow Creek Mudstone|Diastems or hiatuses|None known.|16-MAY-23
75365|Yarrow Creek Mudstone|Relationships and boundaries|Contact with underlying Turquoise Bluff Slate is an inferred fault or faulted unconformity. Contact with overlying Retreat Formation appears conformable.|16-MAY-23
75365|Yarrow Creek Mudstone|Identifying features|This is a pelitic clastic sedimentary unit which consistently occupies the interval between the Turquoise Bluff Slate and the Retreat Formation. Its most distinguishing feature is a geophysical one, i.e. a bright white signature on K-Th-U RGB images of airborne radiometric data, contrasting with the dark signatures of the two adjacent units.|16-MAY-23
75365|Yarrow Creek Mudstone|Structure and Metamorphism|Structural style is upright to steeply inclined, close to tight folds typically with well developed axial planar penetrative slaty cleavage. Later folds with axial planar crenulation cleavage present in some areas. Metamorphism is anchizonal (200-300°C, sub-greenschist facies) according to Patison et al. (2001).|16-MAY-23
75365|Yarrow Creek Mudstone|Age reasons|Probably Silurian. It is the lowest unit of the redefined Panama Group, a conformable sequence of four formations in which the third formation from the base contains late Silurian (Ludlow) graptolites. It is in fault or faulted unconformity contact with the underlying Turquoise Bluff Slate which contains Early Ordovician graptolites.|16-MAY-23
75365|Yarrow Creek Mudstone|Correlations|Correlates probably exist elsewhere within the Mathinna Supergroup outcrop area but none have been identified at this stage.|16-MAY-23
75365|Yarrow Creek Mudstone|Geophysical Expression|Distinctive bright white signature on K-Th-U RGB images of airborne radiometric data, i.e. equally strong signal in all three channels.|16-MAY-23
75365|Yarrow Creek Mudstone|Geochemistry|No data.|16-MAY-23
75365|Yarrow Creek Mudstone|Defn author|David Seymour, Mineral Resources Tasmania, 7-SEP-2010|16-MAY-23
75365|Yarrow Creek Mudstone|Proposed publication|Seymour, D. B.; Woolward, I. R.; McClenaghan, M. P. 2010. Stratigraphic revision and re-mapping of the Mathinna Supergroup west of the Scottsdale Batholith, Northeast Tasmania (Explanatory Report for parts of 1:25 000 scale map sheets Low Head, Tam O'Shanter, Weymouth, Retreat, Lilydale, Bridport, Bowood, Nabowla, Lisle and Patersonia). Mineral Resources Tasmania, 1:25 000 Scale Digital Geological Map Series Explanatory Report 4.; possibly also AJES.|16-MAY-23
75365|Yarrow Creek Mudstone|References|Patison, N. L.; Berry, R. F.; Davidson, G. J.; Taylor, B. P.; Bottrill, R. S.; Manzi, B.; Ryba, J.; Shepherd, R. E. 2001. Regional metamorphism of the Mathinna Group, northeast Tasmania. Australian Journal of Earth Sciences 48, 281-292. [RefID 23167]|16-MAY-23
29475|Zig Zag Hill Formation|Name source|Initial Statement: Corbett et al. (1974) defined the Tyndall Group in the Comstock/Zig Zag Hill area as comprising 2 formations. The lower formation was named the Comstock Tuff (later referred to as the Comstock Formation) and the upper formation was referred to as the Jukes Formation, from an inferred correlation with a previously defined unit, the Jukes Breccia (Hills 1914) or Jukes Conglomerate (Wade and Solomon 1958, Banks 1962, Campana and King 1963). This correlation with the Jukes Conglomerate was subsequently argued to be inappropriate (Solomon 1979, Corbett 1989) and the term Jukes Formation was no longer used. Recently the unit has been referred to informally as the 'upper Tyndall Group' or 'upper part of the Tyndall Group' (e.g. Corbett 1992). There is clearly a need to give this upper unit an appropriate formal formation name, as it is one of two formations that form the Tyndall Group (a group comprises two or more formations; Staines 1985). The term 'Zig Zag Hill Formation' is proposed.                                             Derivation: Zig Zag Hill (geographical location) AMG Grid Reference 5346700N - 382100E Gormanston sheet, Tasmania 1:25 000 series topographical map, Tasmanian Lands Department.|16-MAY-23
29475|Zig Zag Hill Formation|Unit history|The Zig Zag Hill Formation is synonymous with the 'Jukes Formation' of Corbett et al. (1974), and is recently referred to as the upper Tyndall Group (Corbett 1992) (as explained above). The Dora Conglomerate (Bradley 1954) is also considered to be a correlate of the Zig Zag Hill Formation.|16-MAY-23
29475|Zig Zag Hill Formation|Type section locality|A type area (Mount Lyell area) is proposed, rather than a single type section as the formation is well exposed at a number of locations in the Mount Lyell district. The best exposure of this formation occurs on Zig Zag Hill to the north of Mount Lyell, however the upper contact is not exposed there, being masked by Quaternary glacial deposits. Other good exposures occur approximately 1 km along strike to the southeast around the Lyell-Comstock Mine area, where a number of diamond drill lholes intersect the formation (e.g. C50: 187-477 feet, C59: 4601384 feet).  The Zig Zag Hill Formation is also well exposed approximately 4 km further southeast at a place referred to as "East Mount Lyell".|16-MAY-23
29475|Zig Zag Hill Formation|Extent|The formation is exposed in the central part of the Mount Read Volcanics, in western Tasmania from the Mount Lyell district to the Anthony Road/Henty Canal area. Correlates of this unit occur further north in the Mount Cripps Subgroup (Corbett 1992) in the Cradle Mountain Link Road area. Correlates also exist around Mount Selina (McNeill 1987), near Mount Sorell l(Corbett et al. 1993), in the Jukes-Darwin and Mount Huxley area (Corbett et al. 1993) and in the Winterbrook area (Pemberton and Vicary 1989). The Dora Conglomerate (Bradley 1954) is also a correlate of this formation and continues south from Lake Dora to Mount Sedgwick (Corbett and Jackson 1987).|16-MAY-23
29475|Zig Zag Hill Formation|Thickness range|The thickness ranges from approximately 40 m (Henty Canal area) to 500 m thick (Cradle Mountain Link Road area). In type area, the Zig Zag Hill Formation is up to 240 m thick at Comstock and approximately 400 m thick in the East Mount Lyell area.|16-MAY-23
29475|Zig Zag Hill Formation|Lithology|Massive, normally graded and less commonly inversely graded polymict volcaniclastic conglomerate and sandstone beds (m's to several 10's m thick) containing very uncommon units of laminated fine sandstone/mudstone (up to 50 cm thick). Normally graded units consist of clast-supported boulder/cobble/pebble conglomerate at the base and grade up into pebbly sandstone.  Massive units comprise dominantly matrix-supported pebble/cobble conglomerate. Planar diffuse stratification and low-angle cross-stratification is present in some beds. The clast population in the conglomerate beds is diverse but is dominated by subrounded to well rounded, pebble to boulder size, quartz-feldspar porphyritic volcanic clasts in a quartz-, lithic-rich sandy matrix. Other clast types include intermediate-mafic clasts, sedimentary clasts, granite clasts, undifferentiated altered clasts, cherty clasts and metamorphic basement-derived clasts. Details are given in White and McPhie (in prep).|16-MAY-23
29475|Zig Zag Hill Formation|Relationships and boundaries|In most areas analysed, the Zig Zag Hill Formation conformably overlies rocks of the Comstock Formation (lower part of the Tyndall Group). At some locations where the Comstock Formation is missing, the Zig Zag Hill Formation rests unconformably on, or in fault contact with, older Mount Read Volcanic  rocks (e.g. Mount Selina, Mount Huxley, Mount Sedgwick areas).  The upper contact of the Zig Zag Hill Formation is not exposed at Zig Zag Hill, but elsewhere it is both conformably and unconformably overlain by the Owen Conglomerate. At Comstock the Zig Zag Hill Formation is exposed in drill core (Hole C59), and the upper contact is interpreted as an unconformity to the overlying siliciclastic sandstone of the Pioneer Beds (Upper Owen Conglomerate). Approximately 4 km further southeast at a place referred to as "East Mount Lyell" the upper contact of the Zig Zag Hill Formation is gradational and conformable with the overlying Lower Owen Conglomerate.  In the Henty Canal area, the Zig Zag Hill Formation is conformably overlain by the Newton Creek Sandstone (Owen Conglomerate).|16-MAY-23
29475|Zig Zag Hill Formation|Age reasons|The age of the Zig Zag Hill Formation is constrained by fossil dating in underlying and overlying units. Fossils have not been identified in the Zig Zag Hill Formation. Marine fossils found in a brown mudstone unit within the 'Comstock Formation correlates' underlying the 'Zig Zag Hill Formation correlates' on the Cradle Mountain Link Road are dated as late Middle Cambrian in age (Lejopyge laevigata II and III to Damesella torosa-Ascionepea janitrix zones) (Pemberton et al. 1991). The limestone unit in the underlying Comstock Formation at Comstock contains fauna of a similar age (late Middle to early Late Cambrian age: Jago et al. 1972). Fossils in the Newton Creek Sandstone (lower to middle Owen Conglomerate, conformably overlying the Zig Zag Hill Formation in the Henty Canal area) are dated as Post-Idamean to Pre-Payntonian B in age (Corbett 1975, Jago 1979, Banks 1982). Therefore the age of the Zig Zag Hill Formation is between Boomerangian and Post-Idamean to Pre-Payntonian B ages (between approximately 530 and 508 Ma; Shergold 1989).  Recent isotopic U-Pb dating of magmatic zircons in two samples from the underlying Comstock Formation gave two relatively young dates of 494.4+/-3.8 Ma and 502.5+/-3.3 Ma (Perkins and Walshe 1993).|16-MAY-23
29475|Zig Zag Hill Formation|Proposed publication|Australian Journal of Earth Sciences|16-MAY-23
29475|Zig Zag Hill Formation|References|Bradley J., 1954. The Geology of the West Coast Range of Tasmania, Pt 1: Stratigraphy and Metasomatism. P & P Roy. Soc. Tas. v88 p193-243 (01/31642); Corbett K D, 1975. Preliminary report on the geology of the Red Hills-Newton Creek area, West Coast Range, Tasmania. Dept of Mines Tasmania Technical Report 19, p11-25 (79/00952); Corbett K D, 1992. Stratigraphic-volcanic setting of massive sulfide deposits in the Cambrian Mount Read Volcanics, Tasmania. Economic Geology 87, 564-586 (95/28064); Corbett K D, Jackson J C, 1987. Geology of the Tyndall Range area. 1:25000 Map 5. Geological Survey of Tasmania - Department of Mines (96/28179); Corbett K D, Reid K O, Corbett E B, Green G R, Wells K, Sheppard N W, 1974. The Mount Read Volcanics and Cambrian-Ordovician relationships at Queenstown, Tasmania. Journal of the Geological Society of Australia 21, 173-186 (79/00954); Corbett K D, Pemberton J, Vicary M J, 1993. Geology of the Mt Jukes-Mt Darwin area. 1:25000 Map 13. Geological Survey of Tasmania - Department of Mines (96/28186); Jago J B, 1979. Tasmanian Cambrian biostratigraphy - a preliminary report. Journal of the Geological Society of Australia 25, p223-230 (79/20510); Shergold J H, 1989. Australian Phanerozoic timescales: 1. Cambrian biostratigraphic chart and explanatory notes. Bureau of Mineral Resources Australia, Record 1989/31 (RC89/031); Solomon M, 1979. Discussion: Delamerian unconformities in Tasmania. Journal of the Geological Society of Australia 26, p435-436 (80/20782); Staines H R E, 1985. Field geologist's guide to lithostratigraphic nomenclature in Australia. Australian Journal of Earth Sciences 32, 83-106 (86/25146); Wade M L. Solomon M, 1958. Geology of the Mt Lyell mines, Tasmania. Economic Geology 53, 367-416 (Gold 1099); White M J, McPhie J (in prep). Stratigraphy and palaeovolcanology of the Cambrian Tyndall Group, Mount Read Volcanics, western Tasmania. Australian Journal of Earth Sciences (00/30190).|16-MAY-23
