This consultant's interpretation was done to assist with Comalco's trona and petroleum exploration. The crystalline (Carpentarian) basement surface has been delineated at depths ranging from less than 200 m to greater than 3000 m. NE-trending faulting has resulted in a series of NW tilted basement blocks. Early Cambrian sedimentation is inferred to have occurred in a NE trending basin or trough. Late or post-Cambrian fault movements have exposed the basement in the Ammaroodinna area. Further uplift along the Ammaroodinna axis and along a NW axis to the south may have controlled Permian sedimentation. The playa lake environment is inferred to have extended to the SW from the Byilkaoora area, where the potential for trona is most likely. A thick sequence of petroleum source rocks may occur along the axis of the inferred Cambrian basin.