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The Perth Basin is a thick, elongated sedimentary basin in Western Australia. It lies beneath the Swan Coastal Plain west of the Darling Scarp, representing the western limit of the much older Yilgarn Craton, and extends further west offshore. Cities and towns including Perth, Busselton, Bunbury, Mandurah and Geraldton are built over the Perth ...
The scarp forms a divide between the hypersaline groundwaters typical of the Yilgarn Craton basement from the fresh ground waters of the Perth Basin. Some dams along the scarp are contaminated by seepage of saline water from the granite into the base of the dam's water column and must be periodically flushed to preserve water quality.
Basic geological regions of Australia, by age. The large brown region in the lower left of the continent constitutes the Yilgarn Craton. The Yilgarn Craton is a large craton that constitutes a major part of the Western Australian land mass.
Rifting of Australia from India and Africa began in the Permian, resulting in the production of a rift basin and half-grabens of the basal portions of the long-lived Perth Basin. Petroleum was formed in the Swan Coastal Plain and Pilbara during this rifting, presumably in a rift valley lake where the bottom was deoxygenated (akin to Africa's ...
They are deposited unconformably over the Western Zone, overlapping with the deposition of the Kimberley Group. The depositional periods of the sediments, determined from rocks near the bottom of the basin, indicate that the Speewah Basin formed around 1835 Ma, at the same time as the granitic and gabbroic intrusions. [18] [14] [2]
In area, the onshore part of the Carnarvon Basin covers about 115,000 km 2 and the offshore part covers approximately 535,000 km 2 with water depths up to 3,500 m. [10] Less than 5% of the state's gas comes from fields near Dongara, part of the Perth basin, which extends about 1300 km along the southwestern margin of the continent.
The Collie Sub-basin is a pocket of Permian sedimentary rocks with an area of 225 km 2, enclosed within much older Archean rocks of the Yilgarn Craton, near the town of Collie in southwestern Western Australia., [1] [2] Once considered a unique basin, this area, along with the smaller Wilga and Boyup Sub-basins to the south, are now classified as outliers of the Perth Basin, separated from the ...
Basin and range topography has alternating parallel mountain ranges and valleys Basin and range topography is characterized by alternating parallel mountain ranges and valleys. It is a result of crustal extension due to mantle upwelling , gravitational collapse, crustal thickening, or relaxation of confining stresses.