The 1:250000 map sheet area is located in the south-west corner of New South Wales with low relief and consists of sandplains and dunefields. The map area is located entirely within the Murray Basin, a shallow intercratonic basin underlain by the Kanmantoo Fold Belt. The rocks underlying the sediments and sedimentary rocks of the Murray Basin fall within two structural belts, the Glenelg Zone and the Morden-Stawell Zone. The oldest rocks are the Late Proterozoic to Cambrian sedimentary and mafic igneous rocks of the Kars Block. Cretaceous sandstone units are more widespread and covers almost the whole map area. Overlying all earlier units are poorly lithified to unconsolidated sediments of the Tertiary Murray Basin sequences. A few outcrops of lacustrine sediments of LatePliocene to Pleistocene age and aeolian sands have been found. Exploration for heavy mineral sand deposits have been active in the Murray Basin area resulting in the discovery of the Mt Massidon deposit in the Pleistocene Loxton-Parilla sands. The Tararra and Wentworth Infrabasins are considered to have potential for the discovery of petroleum and possibly coal seam methane. Geological and geomorphological features were obtained from aerial photographs, interpretation of lineaments and palaeogeographic features were carried out with the aid of Landsat and NOAA imagery. Field checking and sampling were also carried out and the information were digitised on the Mineral Resource Land Information System.
Ray H.N. (Facer R.A. ed.) 1996. Ana Branch 1:250 000 Geological Sheet SI/54-7: Explanatory Notes. Geological Survey of New South Wales, Sydney, viii+96pp.