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Ceduna Sub-basin

Entity ID: 28505 Compiled by: Totterdell, J. and Rollet, N. Year: 2002 Status: Defined

Last Revised: 2013

Rank: subprovince Type: sedimentary Subtype: polyhistory Location: SA, WA Off-shore

Synonyms: NA Symbol: NA

Minimum age: upper Forcipites longus Age method: biozone

Maximum age: Callovian Age method: inferred, seismic interpretation

Summary: The Ceduna Sub-basin is the main depocentre of the Jurassic to Cretaceous Bight Basin. It contains more than 12 km of siliciclastic non-marine, marine and deltaic rocks.

Attributes:
Area (square kilometres): 126300
State: WA
State: SA
Minimum present water depth (m): 200
Maximum present water depth (m): 5200
Main rock types: siliciclastic sediments and sedimentary rocks
Main depositional environment: marine and non-marine
Maximum sediment thickness (m): 12000
Approximate; may be up to 15000
Present crustal setting: continental
Country: AUS

Parent: Bight Basin

Child Provinces: No data

Relationships:
Adjoins - Couedic Shelf, Duntroon Sub-basin, Eyre Sub-basin, Madura Shelf, Morum Sub-basin, Otway Basin, Polda Basin, Recherche Sub-basin
Underlies - Eucla Basin

Constituent units: Hammerhead Supersequence, Tiger Supersequence, White Pointer Supersequence, Blue Whale Supersequence, Bronze Whaler Supersequence, Southern Right Supersequence, Minke Supersequence, Sea Lion Supersequence

Events: Eyre extension, Mulgara gravity-driven deformation, Ceduna extension, Australia-Antarctica break-up, Kowari gravity slide, Southern Margin Late Cretaceous and Cenozoic magmatism

Mineral Deposits: No data

Key Reference: Bradshaw, B.E., Rollet, N., Totterdell, J.M., Borissova, I. 2003, A revised structural framework for frontier basins on the southern and southwestern Australian continental margin., Geoscience Australia. Record, 2003/03, 44 (Refid:13490)

Comments: No data

Overview: The west-northwest trending Ceduna Sub-basin is the major depocentre of the Bight Basin, and contains in excess of 12 kilometres of Jurassic to Upper Cretaceous sediments. It lies beneath the bathymetric Ceduna Terrace (200 to 5200 m water depth) in the eastern Great Australian Bight. The sub-basin developed during two successive periods of extension and thermal subsidence that commenced in the Middle to Late Jurassic. The middle Cretaceous extensional phase resulted in the Late Santonian break-up of Australia and Antarctica. The northern and northeastern margins of the Ceduna Sub-basin are characterised by a series of fault-bounded half graben containing a syn-rift succession of probable Middle Jurassic to Early Cretaceous age. These are overlain by a Lower to Upper Cretaceous succession that thickens markedly basinward. Jurassic and Early Cretaceous deposition was dominantly non-marine, but from the late Aptian until the end of the Cretaceous deposition took place in mainly marine to deltaic environments. This Upper Cretaceous succession contains thick marine intervals that include potential marine source rocks. The sub-basin is characterised by two periods of deltaic progradation. The Albian to Cenomanian delta is characterised by a mobile substrate, extensive growth faulting and mud diapirism, whereas the Late Santonian to Maastrichtian delta is a sand-rich system featuring strongly progradational stratal geometries. Potential structural and stratigraphic traps are present within both deltaic systems, with the later delta especially containing good potential reservoirs. Indications of active petroleum systems in the sub-basin include oil and gas shows (Greenly 1), and evidence of seepage (slicks, ALF anomalies, stranded asphaltites).

Images: Eastern Bight Basin structural elements and cross-section location map (82 KB), Eastern Bight Basin regional cross-section Profile 2 (68 KB), Eastern Bight Basin regional cross-section Profile 3 (80 KB), Eastern Bight Basin regional cross-section Profile 4 (76 KB), Eastern Bight Basin regional cross-section Profile 6 (41 KB), Eastern Bight Basin regional cross-section Profile 5 (50 KB), Eastern Bight Basin regional cross-section Profile 7 (57 KB), Bight Basin petroleum systems chart (70 KB)

Other media: No data

Source Information:

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This report was generated on Tuesday, July 29, 2014 8:58:46 PM EST.