Australia: The Land Where Time Began

A biography of the Australian continent 

Cervantes-Jurien Area - Northern Perth Basin

A succession from the Lower Permian to the Upper Jurassic is present in the Cervantes-Jurien Area. The Upper Triassic to Upper Jurassic are the only parts of this succession that are exposed, being in a broad anticline feature that is faulted, and is overlain by thin deposits of Cainozoic age (Mory, 1994a; Iasky & Mory, 1996). To the east of the Gingin Scarp, in the elevated central part of the area, the exposures are mostly in the Mount Lesueur National Park, that has a thick cover of vegetation.

The Gingin Scarp is the most prominent feature of the area. Heavy mineral sands accumulated along the Gingin Scarp, the deposition is presumed to have been in the mid-Neogene, in a series of strandlines and dune deposits that are between 30 m and 170 m above the present sea level.

Locality 31 - Jurien Heavy Mineral Sand Deposit. About 20 km north-northeast of Cervantes. Good exposures in which there are small faults in aeolian facies of the Tamala Limestone from the Pleistocene, overlying heavy sand deposit from the ?Pleistocene.

Locality 32 - Lake Thetis, Cervantes. About 1.2 km southeast of the Cervantes post office. On the margin of a small lake that formed in a depression between dunes are microbial mats and stromatolites of Holocene age.

Locality 33 - Pinnacles, Nambung National Park. The Tamala Limestone that formed during the Pleistocene, reprecipitation moving calcium carbonate down around the taproots of trees, the result is the Pinnacle Desert in which the exposed taproots remain above the sand.

Locality 34 - Yallalie Impact Breccia. About 56 km east of Cervantes. Breccia with clasts of greenstone and greensand in a poor road cutting exposure on the edge of what is thought may be an impact crater.

Sources & Further reading

1. Geology of the Northern Perth Basin, Western Australia - a field guide