Abstract

The Kheis Tectonic Subprovince is composed largely of arenitic metasediments and has been described as a thin-skinned fold and thrust belt of Eburnean age ( approximately 1.8 Ga), situated on the western edge of the Kaapvaal Craton. This paper describes the lithostratigraphic framework of the area, and reviews some of the correlations that have been made between various units in the past. The lithostratigraphy and other aspects of the transition between the Kheis Subprovince and the Kaapvaal Craton are discussed. Evidence is presented that the fluvial arenites of the Olifantshoek Supergroup are not continuous into the Kheis Subprovince but terminate against a boundary fault as initially suggested by early investigations. It is proposed that the eastern boundary of the subprovince should be taken at this structure, here termed the Dabep fault. The western boundary involves the transition from Namaqua- to Kheis-aged structures, and several possible positions have been proposed in the area east of Upington. This boundary, as well as other aspects of the "Kheis Orogeny", cannot be fully evaluated until more geochronological data become available. Available ages indicate that the deformational fabric west of the Dabep fault is not Eburnean in age, and it is concluded that the Kheis Subprovince, as defined here, may represent the easternmost extent of the Kibaran Namaqua Orogeny.

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