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Bayerischen Julius-Mawimilians-Universität Würzburg (1999)

An Explanation of the Geological Map 1:10000 of the Namibian borderland along the Orange River at Zwartbas - Warmbad District - Karas Region - Namibia

Geiger Markus

Titre : An Explanation of the Geological Map 1:10000 of the Namibian borderland along the Orange River at Zwartbas - Warmbad District - Karas Region - Namibia

Auteur : Geiger Markus

Université de soutenance : Bayerischen Julius-Mawimilians-Universität Würzburg

Grade : Master Thesis 1999

Résumé
The locality of Zwartbas is situated at the border of Namibia and South Africa about 15 km west of Noordoewer. The mapped area is confined by the Tandjieskoppe Mountains in the north and the Orange River in the south. Outcropping rocks are predominantly sediments of the Nama Group and of the Karoo Supergroup. During the compilation of this paper doubts arose about the correct classification of the Nama rocks as it is found in literature. Since no certain clues were found to revise the classification of the Nama rocks, the original classification remains still valid. Thus the Kuibis and Schwarzrand Subgroup constitute the Nama succession and date it to Vendian age. A glacial unconformity represents a hiatus for about 260 Ma. This is covered by sediments of the Karoo Supergroup. Late Carboniferous and early Permian glacial deposits of diamictitic shale of the Dwyka and shales of the Ecca Group overlie the unconformity. The shales of the Dwyka Group contain fossiliferous units and volcanic ash-layers. A sill of the Jurassic Tandjiesberg Dolerite Complex (also Karoo Supergroup) intruded rocks at the Dwyka-Ecca-boundary. Finally fluvial and aeolian deposits and calcretes of the Cretaceous to Tertiary Kalahari Group and recent depositionary events cover the older rocks occasionally.

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Page publiée le 4 février 2019