Salt and Diapiric Anomalies in the Southeast Bonaparte Gulf Basin

Abstract

The Southeast Bonaparte Gulf Basin comprises a Phanerozoic sedimentary sequence bordered by Precambrian rocks of the Kimberley, Sturt and Darwin Blocks. This portion of the basin developed as a subsiding graben, in which the flanks are separated from the central collapsed area by terraces that foundered to intermediate depths. Geophysical data acquired in the area since 1965 suggest the existence of large quantities of evaporites in the basin. Wells drilled in the area have confirmed the seismic evaluation. These evaporites were initially deposited across existing terraces and basinal areas prior to the later Devonian. Salt and diapiric structures of various types are widely distributed within the basin. The origin and growth of most of these structures is associated with epeirogenic movements along faults that demarcate the major structural elements of the basin.