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Styx Basin

Entity ID: 22644 Compiled by: Taubert, S. Year: 2002 Status: Defined

Last Revised: 2013

Rank: province Type: sedimentary Subtype: intracratonic Location: QLD On-shore and off-shore

Synonyms: NA Symbol: NA

Minimum age: Albian Age method: inferred, biostratigraphic correlation

Maximum age: Early Cretaceous Age method: inferred, biostratigraphic correlation

Summary: The Styx Basin is a small, elongate Early Cretaceous intracratonic sag basin located in central coastal Queensland. It extends offshore and contains less than 1000 m of siliciclastic sediments and coal measures.

Attributes:
Area (square kilometres): 2000
State: QLD
Minimum present water depth (m): 0
Maximum present water depth (m): 100
Main rock types: siliciclastic sediments and sedimentary rocks
Main rock types: organic-rich sediments and sedimentary rocks
Main depositional environment: non-marine
Minimum sediment thickness (m): 387
Maximum sediment thickness (m): 900
Resources: Coal - undifferentiated
currently uneconomical
Present crustal setting: continental
Country: AUS

Parent: No data

Child Provinces: No data

Relationships: None

Constituent units: Styx Coal Measures

Events: No data

Mineral Deposits: Styx

Key Reference: Department of Resource Industries 1989, Petroleum Resources of Queensland: Review to June 30, 1989, Petroleum Resources Assessment and Development Subprogram, Department of Resource Industries, Queensland, , 145-147 (Refid:12563)

Comments: No data

Overview: The Styx Basin is a small Early Cretaceous intracratonic sag basin straddling the central Queensland coast near the town of St Lawrence. The basin covers an area of approximately 2000 sq. km, and extends offshore to water depths of up to 100 m. Maximum known thickness of sedimentary rocks is 387 metres in an onshore coal exploration bore, but magnetic data suggest the basin thickens offshore to the north. The Styx Basin probably developed by subsidence of the Strathmuir Synclinorium, an older feature containing Permian Bowen Basin strata. Styx Basin sediments lap onto Permian strata in the west, and are faulted against them in the east. The basin plunges gently to the north under the waters of Broad Sound, however the general dip of the Styx Coal Measures is to the east. The southern part of the basin is bounded to the east by a post-depositional high-angle reverse fault. Adjacent to this fault, the Cretaceous sedimentary rocks are folded and faulted. The known strata of the basin are referred to as the Styx Coal Measures and consist of quartzose, calcareous, lithic, and pebbly sandstones, pebbly conglomerate, siltstone, carbonaceous shale and coal. The environment of deposition was freshwater, deltaic to paludal with occasional marine incursions. The coals at the base of the Styx Coal Measures lie within the oil window and could potentially generate petroleum, however, there is no known evidence that generation of oil or gas has occurred from this succession. The offshore Styx Basin lies entirely within the Great Barrier Reef Marine Park, in which petroleum exploration activity is prohibited. Coal was mined in the first half of the 20th century with a total production of 1.76 million tonnes, but reserves are currently not of economic importance.

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This report was generated on Wednesday, July 23, 2014 5:33:08 AM EST.