The GASON 1:250,000 map area is located in the northeast of South Australia, on the Birdsville Track. The map area includes the Gason, Dome, a topographically low structure with a northeasterly trending axis, and shallow dips on its flanks. The Upper Cretaceous Winton Formation is the oldest outcropping stratigraphic unit, which, although extensive, is very poorly exposed. Silcrete is the major Tertiary unit, generally consisting of collapsed boulders rather than solid plateaus. Quaternary units are extensive throughout the map area. The oldest of these is a gypsite profile, and there is a younger soil profile which has been reworked from the gypsite. Northwesterly trending sand dunes surround and lap onto the Gason Dome, the centre of which is covered mainly by silcrete gibbers. A vast flood plain of The Warburton and The Diamantina covers the area to the northwest of the structure.