Geothermal Energy Potential in Selected Areas of Western Australia ...

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2. Perth Basin Geological Setting
The Perth Basin is a north-northwesterly oriented rift basin extending approximately
1000 km along the western margin of south-western Australia, between latitudes
27°00’S and 34°30’S. It is comprised of a series of sub-basins, troughs, shelves and
ridges containing predominantly Early Permian to Late Cretaceous sedimentary
sequences up to 15 km thick (Freeman and Donaldson 2006 1 ). The Basin extends
from the Darling Fault in the east, which marks a discontinuity between the
Phanerozoic sediments of the basin and the Precambrian rocks of the adjacent
Yilgarn Craton, to the edge of the continental shelf to the west. To the north the basin
grades into the Southern Carnarvon Basin. Precambrian rocks of the Pinjarra Orogen
underly the Perth Basin. These crop out as fault bounded mid-basin ridges in the
Leeuwin and Northampton Complexes (Mory et al., 2005 2 ).
The Perth Basin is structurally complex and formed during the separation of Australia
and Greater India in the Permian to Early Cretaceous. The structural architecture of
the Perth Basin is the product of oblique rifting during the Permian, Late Triassic to
Early Jurassic and Middle Jurassic to Early Cretaceous, superimposed over preexisting
basement terrains (Mory and Iasky, 1996 3 ). Extension during the Permian
produced the series of deep, north-south trending rift basins (Bunbury Trough and
Dandaragan Trough) along the western margin of the Yilgarn Craton with syndepositional
growth along the Darling Fault.
Breakup was associated with widespread inversion, erosion, strike-slip tectonics and
volcanism, which significantly modified the structural architecture of the Perth Basin.
Major structural elements associated with breakup tectonism include an area of
1
Freeman, M. J., And Donaldson, M. J., 2006, Geology of the southern Perth Basin and Margaret River wine
district, southwestern Western Australia — a field guide: Western Australia Geological Survey, Record 2006/20
2
Mory, A. J., Haig, D. W., Mcloughlin, S., And Hocking, R. M., 2005, Geology of the northern Perth Basin,
Western Australia— a field guide: Western Australia Geological
Survey, Record 2005/9
3
Mory, A. J., And Iasky, R. P., 1996, Stratigraphy and structure of the onshore
northern Perth Basin, Western
Australia: Western Australia Geological Survey,
Report 46
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