Petermann Orogeny

The Petermann Orogeny was an Australian intracontinental event that affected basement rocks of the northern Musgrave Province and Ediacaran (Proterozoic) sediments of the (now) southern Amadeus Basin between 630-520 Ma.

Exhumation of the Musgrave Block (and overlying sediments) resulted in successive unroofing and deposition of rock types such as arkose and conglomerate in localised sedimentary basins that now outcrop as Uluru and Kata Tjuta respectively.

Several northeast trending discontinuities including the Mundrabilla lineament divide the Petermann orogeny, with extensive vertical offsets across them, usually west-side-up, though the timing of this event is unknown.

Six deformations are known (to be completed) Foliations associated with the Petermann Orogeny are typically steeply to gently south-dipping and subparallel to the thrust faults upon which they were developed.

S regionally pervasive stretching lineation is potentially associated with some of these faults, especially in the deeper areas of the crust which have been exhumed, because these were within the temperature and pressure conditions for brittle-ductile and ductile deformation.

The unusual geometry of this east-west tending orogenic belt suggests that during the formation of the supercontinent Gondwana 550 million years ago, India collided with Western Australia from the northwest, rather than from the west, with deformation accommodated along a zone of crustal weakness and pre-existing fault lines.

In order to provide work, subsidised exploration was undertaken by the Western Mining Corporation, resulting in the discovery of podiform copper at Warburton Range, and eventually the Wingelinna nickel laterite resource.