By tracing lineaments from the land into the adjacent Sahul Shelf, previous authors speculated that the bathymetric rises on the shelf correspond to areas of relatively shallow Precambrian rocks, and a bathymetric depression to deeper Precambrian rocks. A recent aeromagnetic survey confirms these speculations: the bathymetric depression corresponds in detail with the axis of a non-magnetic section 6 km thick, and the bathymetric rises with crests of a thinner non-magnetic section. The shelf morphology is thus a subtle reflection of regional structure, and originated by the rejuvenation of very ancient structural patterns. In the adjacent Timor Trough, the submarine morphology does not correspond with the depth of the magnetic basement, indicating a different kind of structural history.
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|Published - Aug 1967