Entity ID: 529727 Compiled by: Stewart, A.J. Year: 2010 Status: Defined
Last Revised: 2013
Rank: province Type: sedimentary Subtype: intracratonic Location: QLD On-shore
Synonyms: NA Symbol: NA
Minimum age: Mesoproterozoic, 1140 ± 95 Ma Age method: inferred, overlying unit
Maximum age: Mesoproterozoic, 1560 ± 14 Ma Age method: inferred, underlying unit
Summary: Concealed basin overlying probable Mesoproterozoic basement with four interpreted bodies of granite. May be potential geothermal target, as neighbouring outcropping granites (Williams Batholith) have high levels of K, Th, and U. Two outcrops of schist and gneiss within basin outline at long. 141.157, lat -19.611, and 141.396, -19.771 may be Proterozoic basement inliers or metamorphosed rocks of Millungera Basin sequence.
State: QLD Country: AUS
Parent: No data
Child Provinces: No data
Overlies - Soldiers Cap Domain
Underlies - Eromanga Basin [With angular unconformity]
Constituent units: Mount Fort Bowen Sandstone
Events: No data
Mineral Deposits: No data
Key Reference: Carr, L.K., Korsch, R.J., Jones, L., Holzschuh, J. 2010, The role of deep seismic reflection data in understanding the architecture and petroleum potential of Australia's onshore sedimentary basins (extended abstract), APPEA Journal and Conference Proceedings, 50, no page numbers in abstracts section (Refid:66570)
Comments: Maximum age from U-Pb SHRIMP date on detrital zircon from basin sequence (Neumann & Kositcin, 2011, p.69). Minimum age (hydrothermal overprint) from Rb-Sr by Tonguc Uysal on illite in GSQ Dobbyn 2 into basin (pers comms I.Withnall, GSQ, May 2012)
Overview: Concealed basin of unknown age found in 2006 by seismic survey. It is about 280 by 95 km in extent, and overlies probable Mesoproterozoic basement with four interpreted bodies of granite. Unconformably overlain by Toolebuc Formation. Contains about 1500 m of sedimentary rocks in N (seismic line 07GA-IG1 NE of Quamby), with three internal sequences evident. Base of basin is at maximum depth of 3200 m (seismic line 07GA-IG). Gravity profiles suggest deepens to 4000 m in S (E of Cannington). Both E and W margins of basin cut by thrust faults verging towards basin. Hanging-wall antiforms are located above the thrust faults at eastern margin. Potential for hydrocarbons unknown at this stage (no drilling). May be potential geothermal target, as neighbouring outcropping granites (Williams Batholith) have high levels of K, Th, and U; the E-most underlying interpreted granite is low-density and hence silicic, and is blanketed by the thickest part of the Millungera Basin (4000 m), and so may be best target.
Basin outline encloses two tantalising outcrops of NE-dipping Proterozoic metasediments at lat. -19.611, long. 141.157 (Mt Fort Bowen), and at lat. -19.771, long. 141.396 (Mt Brown). Their NE dip and NW strike, parallel to nearby basin outline, are consistent with their being exposures of basin sequence, or of basement below basin sequence.
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