Musgrave Block

The Musgrave Block (also known as the Musgrave Province) is an east-west trending belt of Proterozoic granulite-gneiss basement rocks approximately 500 kilometres (310 mi) long. The Musgrave Block extends from western South Australia into Western Australia.

The Musgrave Block is primarily exposed through the actions of the Petermann Orogeny at c. 535-550 Ma, which exhumed the orogenic belt along the Woodroffe Thrust.

The Musgrave Block is currently passive geologically, with surficial processes described as residual erosion. The area currently experiences on average less than 150mm (6 inches) of rainfall per annum, which provides little surface runoff and hence virtually no erosion.

The landforms of the area are primarily composed of wide calcrete plains, often covered by Age aeolian deposits of sand dunes, sometimes reworked into ephemeral sheetwash fans. Outcrop is rare, restricted primarily to the igneous rocks of the Giles Complex and several granite domes, gneiss domes and isolated outcrops.

This area is also a distinct physiographic province of the larger West Australian Shield.

Several Palaeozoic to neoproterozoic sedimentary basins onlap the Musgrave Block, and are exposed mostly around its edges. These were derived from erosion of the Musgrave Block basement during the neoproterozoic to Permian.

The Proterozoic of the Musgrave Block is composed of seven main classes of rocks;

The Musgrave Block is flanked by several Proterozoic to Palaeozoic sedimentary basins, whose sedimentary history can elucidate the timing of tectonic events in the Musgrave Block post-1080 Ma. These include the Proterozoic Amadeus and Officer Basins.

The most illustrating way of considering the Musgrave Block is as part of a time-space plot in which geological events are arrayed in time against rock units, stratigraphic relationships and for correlative purposes.

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