The Lander Trough forms the east-southeast trending, southern and deeper part of the Wiso Basin, and is flanked on the north by an extensive less deformed area of the Basin. Recent geological mapping, shallow stratigraphic drilling, and a reassessment of geophysical data in the southeastern part of the trough provide additional information on the nature and structure of the rocks it contains. Beneath the Cainozoic superficial material, three sequences of rocks are distinguished. The upper sequence consists of ?Late Palaeozoic Lake Surprise Sandstone; the middle of Cambrian or Ordovician sediments and volcanics; and the lower of Proterozoic rocks. The ?Late Palaeozoic sequence is flat-lying and thin (100-250 m), whereas the Early Palaeozoic sequence forms a wedge which thins to the north and thickens southwards to about 800 m In the deepest part of the trough. The Proterozoic sequence forms the basement to these Palaeozoic sediments of the Wiso Basin. The trough is indicated to be a downwarp in the crust, about 300 km long and 100 km wide, bounded by an overthrust fault system against the Arunta Block on the south. The fault system is considered to be contemporaneous with the post-Devonian Alice Springs Orogeny which affected the NgaIia and Amadeus Basins farther to the south. The presence of a thick (up to 800 m), partly marine sequence of Cambrian and Ordovician sediments upgrades the petroleum potential of the Lander Trough area, as gas has been found in such sediments in the depositionally and structurally similar Amadeus Basin to the south, and the Toko Syncline of the Georgina Basin to the southeast.
