The Murray Basin is an intracratonic basin filled with Cainozoic fluvial to shallow marine sediments. Deposition in the Eocene and early Oligocene was characterised by floodplain and swamp deposits, emplaced with occasional interbeds of shelly clays and limestone. The peak of a marine incursion in the Mid-Miocene resulted in the deposition of thick packages of marine clays and limestones. A more rapid marine transgression at the end of the Miocene led to highstand deposition in the Pliocene, and resulted in the progradation of the littoral Loxton-Parilla Sands and shallow marine Bookpurnong Formation. Pleistocene deposition was dominated by lacustrine clay and variably dolomitic limestone within the ancient Lake Bungunnia. The modern land surface of the north-western Murray Basin consists of aeolian, alluvial and colluvial cover. Prograding shorelines resulting from the basin-wide regression in the Plio-Pleistocene are now host to a number of heavy mineral sand prospects across the Murray Basin. Over 40 discrete beach deposit strandlines can be identified in the north-western Murray Basin. Crystalline basement to the basin consists of Neoproterozoic to Cambro-Ordovician meta-sediments and Cambrian-Ordovician igneous intrusives and extrusives. Basement architecture is dominated by the Devonian Renmark Trough and Canegrass Lobe. These tectonic features host the Devonian to Permian Nadda Basin and Cretaceous Berri Basin that underlie the Cainozoic Murray Basin. The majority of the exploration done in the north-western Murray Basin has been for heavy minerals. A number of anomalous strandlines have been defined, however, assemblages have been dominated by ilmenite and iron oxides. There are numerous gypsum deposits scattered throughout the Murray Basin. The gypsum is thought to have originally formed when Lake Bungunnia began to dry up about 600,000 years BP, and fragmented into separate saline playas. Exploration for most other commodities has concentrated on the margins of the basin, around pre-basinal metamorphic rock or crystalline basement outcrop and subcrop where a number of gold and copper prospects have been defined. Exploration of the basement has been sparse.