Musgrave Province

Age Sedimentation and igneous intrusion/extrusion - Palaeoproterozoic to Mesoproterozoic (~1600 Ma and ~1300 Ma). Felsic/(mafic) intrusions (Pitjantjatjara Supersuite) and deformation by Musgravian Orogeny (~1200 Ma). Layered ultramafic-mafic-anorthosite intrusions (Giles Complex), Alcurra Dolerite and Angatja Granite (~1070 Ma). Regional Amata Dolerite dyke swarm (~800 Ma) equivalent to the Gairdner Dyke Swarm. Sedimentation around block margins (Officer Basin) and localised internal basins (Levenger and Moorilyanna Grabens) (~820 to ~540 Ma). Petermann Orogeny (~540 Ma) - crustal shortening with strain distribution varying from partitioning in thrust faults, to regional penetrative fabric, to basement and cover coupling in thrust nappes. Significant epidote-quartz alteration and faulting during Alice Springs Orogeny (~380 Ma).   Prospective commodities Ni, Cu, PGE, Au, Pb, Zn, chromite, V, ilmenite, RRE, U, W, Sn, opal, diamonds, rubies, chrysoprase, magnesite, S. Major exploration models Ultramafic-hosted nickel sulphide and PGE Stratiform chromite cumulates Stratiform titaniferous magnetite cumulates Laterite nickel deposits VHMS in basement meta-volcanics Sediment-hosted copper and zinc in basement metasediments Diamonds in kimberlites along major structures.

Summary geology

The region discussed in this section, is largely incorporated within the Anangu Pitjantjatjara Yankunytjatjara (APY) Lands, and includes crystalline Mesoproterozoic basement rocks of the Musgrave Province proper, as well as adjacent parts of the Officer (Neoproterozoic and Palaeozoic), Arckaringa (late Palaeozoic) and Eromanga (Mesozoic) Basins.

The APY Lands lie in the far northwest corner of South Australia. They cover all of the 1:250 000 map areas of MANN, WOODROFFE, ALBERGA, BIRKSGATE, LINDSAY and EVERARD; the western parts of ABMINGA and WINTINNA; and the northern fringes of NOORINA, WELLS and GILES, comprising a total area of 102 630 km².

Mineral exploration was conducted by companies and South Australian Department of Mines from about 1953 until 1981, when the Pitjantjatjara Land Rights Act (now the Anangu Pitjantjatjara Yankunytjatjara Land Rights Act 1981) was proclaimed. The main target minerals were nickel, base metals, uranium, gold, rare earths, evaporites, hydrocarbons and coal. This work yielded sub-economic deposits of secondary nickel and encouraging discoveries of copper, heavy mineral sands, rare earths, hydrocarbons, evaporites and uranium. Prospectors made commercial finds of opal and chrysoprase.

There was no mineral exploration in the APY Lands, apart from precious stones prospecting, between 1981 and 1998. Sporadic exploration continued on the eastern end of the Musgrave Province throughout this period. The APY Executive has since recognised the potential benefits that mineral exploration and production could provide to the APY and has begun the process of opening the lands to exploration.

PIRSA Minerals and Energy Resources Division Geological Survey Branch officers have now released a Summary report (.pdf 3.16Mb, opens in new window) outlining all exploration and geological mapping work completed on outcrops of Giles Complex within four small areas of the western Musgrave Ranges.

In November 2009 PIRSA released four areas located within the APY Lands for Mineral Exploration Licence applications. These applications are currently under consideration.

The proclaimed precious stones field at Mintabie (EVERARD) was the world’s largest producer of precious opal in the late 1980s and early 1990s. A small quantity of chrysoprase has been recovered from deposits near Mount Davies (MANN).