The WOODROFFE 1:250,000 sheet area occupies part of the Musgrave Block in the North West Province of South Australia. It includes the western part of the Musgrave Ranges and the northern limits of the Great Victoria Desert. The oldest rocks are gneisses of the granulite - and amphibolite - facies which have resulted from the high grade regional metamorphism of sedimentary and basic igneous rocks during the late Carpentarian - lower Adelaidean. These gneisses have been intruded by charnockites, granites, basic rocks (equivalent to the Giles Complex) and basic dyke rocks. These rocks have been affected by regional-scale normal faults and a thrust fault during Adelaidean time when, also, a very thick sequence of feldspathic clastic sediments was deposited south of the Musgrave Ranges. Deep weathering during the Tertiary was followed by the deposition of a shallow, brackish water fossiliferous. limestone in the Tertiary - Quaternary. The Quaternary Period was marked by an alternating wetter and dryer climate resulting in the development of calcrete, a red sandy soil and extensive sand dunes, sand spreads and alluvium.