Abstract

In this study four subparallel faults have been recognised in the Eiseb Block in the field and in Landsat TM 5 scenes. Their extension into Botswana’s Gomare and Kunyere faults, which delineate the Okavango Rift/Botswana, has been traced. In the Eiseb Block abrupt termination of Kalahari dunes corresponds with northeast-southwest trending tectonic lineaments, whereas a second set of north-northwest to south-southeast orientated lineaments is evident from the orientation of rivers. The two systems intersect in the central part of the study area. Weighted lineament trends show peaks at northeast to southwest (41° to 50°) and north-northwest to south-southeast (151° to 160°). A field survey revealed small extensional faults of corresponding orientation. The fact that Kalahari dunes are displaced since their last active phase shows that the faulting is post-35 to 28 ka. However, the Eiseb Graben and associated lineaments seem to be a long-lived, probably reactivated structure that follows the pre-existing structures of the Damara inland branch, Karoo trough, and basin structures of the Kalahari.

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