The Officer Basin covers about 300,000 square km and is largely concealed beneath sediments of the Gibson and Great Victoria deserts in western and southern Australia. Approximately two-thirds of the Officer Basin lies in Western Australia. Extensional faults have been recognised in Late Proterozoic sequences of the north-eastern part of the basin. There are several sub-basins or troughs of thick sediment accumulations, such as the Munyarai and Wintinna troughs. In the south the Tallaringa Trough also contains substantial thicknesses of Late Proterozoic and Cambrian sediment. Southward - directed thrusting of the Musgrave Block along the northern margin of the Officer Basin has long been recognised, but in the late 1980s seismic lines also outlined several thrusts along the basin's south-eastern margin that dip shallowly to the north. These thrusts have affected Cambrian sequences and may be equivalent in age and style to the Alice Springs Orogeny. The basin contains thick bedded and diapiric Neoproterozoic halite in the Alinya Formation and its equivalents elsewhere in the Centralian Superbasin (such as the Gillen Member in the Bitter Springs Formation of the Amadeus Basin). Weathered diapir crests outcrop as near surface caprocks in the western parts of the basin. Seismic records from the eastern part of the basin show that thrust faults have re-activated salt movement in some Neoproterozoic extensional diapirs. Cambrian, metre-to-decimetre scale cyclic halite beds occur above and below the Ouldburra Formation - Relief Sandstone contact throughout much of the South Australian part of the basin. Actual halite, not just its pseudomorphs, has been recovered in drillholes Manya 6 of the eastern Officer Basin and Wilkinson 1 in the Tallaringa Trough. Evaporite pseudomorphs after long-vanished continental Cambrian evaporites also occur in the Parakeelya Member of the Observatory Hill Beds. The lower interval of Officer Basin strata penetrated by Wilkinson 1 (573.7-677.8 m depth KB) entrains 16 salt beds that are dominated by chaotic halite textures. Beds of this impure salt make up an aggregate thickness of 51.93 m in a total interval thickness of 104.1 m. Besides the dominant texture of chaotic halite, vertically-aligned halite, displacive halite, karst-fill halite and fibrous halite intervals have been identified within the salt beds. The salt beds are separated by redbed mudstones with occasional nodular anhydrite horizons and thin dissolution breccias that indicate former salt beds. A substantial portion of the salt in Wilkinson 1 has been dissolved by through-flushing subsurface waters. Tops of most of the salt beds show evidence of dissolution and collapse. Most of the dolomitic/calcitic mudstones associated with the salt beds show a green colour indicating the presence of the reduced (ferric) form of iron, in contrast to the presence of the oxidised (ferrous) form of iron in the redbed matrix. The envisaged overall depositional setting was a stacked series of ephemeral pans and saline mudflats in the distal alluvial portion of an arid continental landscape. These wet saline mudflats were composed of sheet-flood sediments in which the lamination and dessication structures were destroyed by the growth of abundant intrasediment evaporite crystals. Beds of chaotic/displacive halite grew a few centimetres to metres below the surface in capillary zones within saline mudflat areas that were occasionally covered by thin brine sheets. These surface water sheets precipitated crusts of chevron halite as they dried up rapidly. With burial these salt beds were subjected to ongoing alteration until the adjacent claystone beds were compacted and cemented to a point where they lacked permeability.