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Current Projects
Concluded Projects
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Updated:
21 June 2007
Concluded: 30th June 2000
Lachlan Fold Belt Project (1991 - 2000)Figure 1. Outcrop/subcrop distribution of the Lachlan Fold Belt in New South Wales and Victoria, and 1:250 000 map sheet areas. IntroductionThe Lachlan Fold Belt NGMA Project, a collaboration between Geoscience Australia (GA), NSW Department of Mineral Resources (NSWDMR), and the Victorian Department of Natural Resources and Environment, was concluded in June 2000. The Lachlan Fold Belt (LFB) has a long history of mineral production including gold, copper, lead, zinc, silver, and tin. The potential for new discoveries in the LFB is high, and the scientific input from the project played a leading role in focussing exploration effort. The project commenced in 1991 with the following major objectives:
Major activities included:
Project highlights
Following the completion of field mapping on the Bathurst sheet in 1994, a field conference based in Orange was held to present preliminary research results and maps. The conference excursion guide is available from the NSWDMR. A comprehensive digital GIS package for the Bathurst 1:250 000 sheet was released in March 1997. The package includes layers for outcrop geology, derived geology (interpretive pre-Tertiary geology, cross-sections, etc), geochemistry, site observation and structural data, petrology, and mineral occurrence, fossil, geochronology, and photographic databases. The 2nd edition Bathurst 1:250 000 scale geology map and a comprehensive explanatory notes volume were released in 1998. The six component 1:100 000 scale geology maps and complementary regolith landform maps are also available.
The second edition 1:250 000 scale Dubbo geological map and explanatory notes were released in 1999. As with the Bathurst sheet, the explanatory notes were the first published for the Dubbo area and contain detailed descriptions of over 200 units, as well as summary chapters on tectono-stratigraphic history, structure, metallogenisis, and coal geology. A field conference was held in April 1997 to mark release of the preliminary second edition of the Dubbo 1:250 000 sheet. A conference excursion guide and digital GIS package of the Dubbo 1:250 000 sheet is available from the NSWDMR.
The most recent project activity centred on the Forbes 1:250 000 sheet. Field mapping was completed in 1998, and a field conference, with accompanying excursion guide, was held in April 1999. A new second edition 1:250 000 geological map, along with regolith and basement geology maps, were released in 2000. In addition, a new style of map was released which illustrates the depth to bedrock in a region which is substantially covered by Quaternary alluvial sediments. This map is of use to mineral explorers in planning exploration programs, and hydrologists in delineating groundwater flow in the Quaternary sediments which are up to 150 metres thick.
A comprehensive explanatory notes and GIS data package on CD accompany the new maps for the Forbes sheet. A major SHRIMP U-Pb zircon geochronology study was included in the Forbes project, greatly enhancing interpretation of the age of volcanic and associated sedimentary sequences, the timing of plutonic and deformation events and their relations to mineralisation.
Airborne geophysical data for the Goulburn 1:250 000 sheet area were acquired and released in 1997.
Final editions of the Willaura and Skipton 1:100 000 geological maps in central Victoria were completed in June 2000. The maps, and an explanatory notes record for the Willaura sheet, are available through Geoscience Australia and the Victorian Geological Survey. Airborne geophysical data were also acquired for the Ballarat 1:250 000 sheet.
Airborne geophysical data for the Cootamundra 1:250 000 sheet area were acquired in 1998. A 1:250 000 scale basement geology interpretation of the geophysical data and previous outcrop mapping was released in 1999.
Airborne geophysical data and a preliminary geological map were released in 1993.
1997 Survey - The AGCRC completed a deep seismic reflection acquisition program in the eastern Lachlan Fold Belt in 1997. Three reflection lines were acquired (total line length of about 105 km). A north-south line through the Lachlan Transverse Zone was designed to image north-dipping structures that escaped the subsequent strong east-west shortening. This line is located near the Cadia and Forest Reefs deposits and the Forest Reefs area. The other two lines (one through Molong and the other to the east of Orange) form part of an east-west section designed to provide structural details from the Cowra Trough in the west, across the Molong volcanic belt to the Mumbil Shelf, and Hill End Trough in the east. Line 2 is near the Mt Bulga and Lewis Ponds deposits, and Line 3 is just south of the Copper Hill deposit. The AGCRC also carried out a crustal refraction experiment in the eastern Lachlan Fold Belt in July 1997. The 300+ km north-south profile from near Gundaroo, to a point east of Dubbo, followed the Molong volcanic belt and was designed to provide information on the distribution of mafic volcanic and sub-volcanic rocks in the crust, particularly comparing the nature of the crust in the Lachlan Transverse Zone with the crust to the north and south of this zone. Around 3000 samples were collected at half drill rod intervals (2.25 m) along all three reflection traverses. Vital information was obtained on regolith profiles over varying bedrock types in a range of geomorphic environments. Evidence for postulated palaeodrainage was gained, as was an indication of the pre-Mesozoic sedimentation over this part of the Lachlan Fold Belt. 1999 Survey - The AGCRC completed a second survey in 1999 involving three lines across the Gilmore Fault Zone and Lake Cowal Volcanic Complex. Preliminary results of the survey were presented at the 15th Australian Geological Convention in Sydney in July 2000, highlighting steep east-dipping faults linked to a major shallow west-dipping thrust surface in the Gilmore Fault Zone. A workshop attended by around 50 industry, university and government geologists was held in Orange in March 2001 to present the final seismic interpretations and a crustal architecture synthesis covering the area from the Nyngan sheet in the north-west to Goulburn in the south-east. Figure 4. Location of AGCRC seismic lines (1997 - eastern lines; 1999 - western lines) overlain on a basement geology synthesis map of the north-eastern Lachlan Fold Belt. The map extends from the Nyngan 1:250 000 sheet in the north-west to Goulburn in the south-east. Project contactsProject managersPatrick Lyons (GA) 02 6249 9763 (ph), 02 6249 9917 (fax) Ted Tyne (NSWDMR) 02 9901 8302 (ph), 02 9901 8256 (fax) Peter O'Shea (VDNRE) 03 9412 7871 (ph), 03 9412 7803 (fax) GA project staffPatrick Lyons - Regional geology, structural geology Ollie Raymond - Regional geology, GIS Terry Mernagh - Economic geology, Laser Raman microprobe (part-time) Lance Black - U-Pb zircon geochronology (part-time) PartnersNew South Wales Department of Primary Industries | Minerals Victorian Department of Primary Industries | Minerals & Petroleum Cooperating agenciesAustralian Geodynamics CRC Australian National University NSW Department of Infrastructure, Panning and Natural Resources Maps, reports, digital data
1:250 000 scale mapsGeology
Basement geology
Regolith landforms
Depth to bedrock
1:100 000 scale mapsGeology maps and Regolith Landforms maps - BathurstGeology maps and Regolith Landforms maps - ForbesGeology maps - DubboGeology maps - Ballarat
Explanatory notes
Field conference excursion guides and abstracts
Digital Geology Data (GIS Packages on CD)Airborne geophysical dataMagnetics, radiometrics (and some digital elevation data) at 200-400m line spacing are available for the following 1:250 000 sheets:
Detailed gravity data (ca. 4 km station spacing with some more detailed areas) are available for the following 1:250 000 sheets:
Other publications (1996 to 2000)(GA authors in bold font) 2000
1999
1998
1997
1996
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