Title:

New aspects of lithostratigraphic subdivision and correlation of late Proterozoic to early Cambrian rocks of the southern Damara Belt and their correlation with the central and northern Damara Belt and the Gariep Belt

Author(s):
Publication Year:
1989
Abstract:

Results from stratigraphic studies in the southern Damara Belt allow detailed correlations between the metamorphic Damara Sequence of the internal Hakos Terrane, and low-grade to non-metamorphic units of the external Naukluft Nappe Complex and foreland succession. The oldest units comprise the Bitterwater, Doornpoort, Klein Aub and Eskadron Formations which were previously included in the pre-Damara Sinclair Sequence, but are now grouped into a new major, lowermost division of the Damara Sequence, the Tsumis Group. They are followed by the Nosib Group, which forms the base of the Damara Sequence elsewhere in the Damara Belt. Metamorphic units of the Kudis and Vaalgras Subgroups (Hakos Group) are shown to represent deep-water facies equivalents of dominantly shallow-water marine carbonate-bearing units of the Naukluft Nappe Complex, the Court and Buschmannsklippe Formations of the new Witvlei Group (Hegenberger, in prep.), and the lower Nama Kuibis Subgroup. Two discrete glaciogenic units, represented by the older Blaubeker Formation and the younger Naos and Blasskrans Formations, are recognized. Stratigraphic evidence from the Gariep Belt indicates correlation of the basal Stinkfontein Group with the Nosib Group and of the overlying Hilda Subgroup and the Holgat Formation with the Kudis Subgroup-Court Formation and the lower Vaalgras Subgroup-Buschmannsklippe Formation and their stratigraphic equivalents in the Naukluft Nappe Complex, respectively. The lower Kaigas Formation tillite occurs in a stratigraphic position corresponding to that of the Blaubeker tillite, while the upper Numees Formation is shown to be a correlate of the Naos and Blasskrans Formations. Correlations between the southern Damara Belt and the central and northern Damara Belt indicate that the Kudis Subgroup and Court Formation are to be correlated with the Khomas Subgroup, comprising the Karibib Formation, the Tinkas Formation, and the older, pre-tectonic parts of the Kuiseb Formation in the Swakop and northern Khomas Terranes, and the Tsumeb Subgroup of the northern foreland and Owambo Basin. The Blaubeker Formation tillite thus corresponds to the Chuos Formation, while the Naos Formation, which has been traditionally equated with the Chuos Formation, is believed to be much younger and to correspond to the regional unconformity which separates the Tsumeb Subgroup from the overlying Mulden Group. Accordingly, it is suggested that the latter is stratigraphically equivalent to the Vaalgras Subgroup and Buschmannsklippe Formation of the upper Witvlei Group and, probably, also the Kuibis Subgroup of the lower Nama Group. Stratigraphic equivalents of these units in the central metamorphic zones of the Damara Belt are believed to be the younger, syn-tectonic parts of the Kuiseb Formation of the Khomas Terrane.

Publication Title:

Communications of the Geological Survey of Namibia

Publisher:
Geological Survey of Namibia
Volume:
5
Pages:
61-70
Item Type:
Journal Article
Language:
en
Keywords:

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