The stratigraphy and structural evolution of the late Proterozoic Gariep belt in the Sendelingsdrif-Annisfontein area, northwestern Cape Province
Doctoral Thesis
1988
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University of Cape Town
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Abstract
A geological investigation of the Port Nolloth metasediments in the central external parts of the Gariep Beit has led to a re-interpretation of tbeir lithostratigraphy and Pan-African geotectonic evolution. During the rifting stage of passive continental margin evolution, the basal elastic Stinkfontein Sequence was deposited in an alluvial fan environment. Fluviatile conglomerates and quartz arenites (Lekkersing Formation) interfinger with feldspathic arenites and minor volcanics (Vredefontein Formation), and prograde into marginal marine elastics and carbonates (Gumchavib Formation). Rift faulting produced local grabens into which massflow sediments (Kaigas Formation) and volcaniclastics (Rosh Pinah Formation) were shed. During the sea-floor spreading stage, a shallow-water carbonateclastic unit, the Hilda Sequence, was deposited. Conglomerates, quartzites, and schists with resedimented gravity-flow characteristics (Wallekraal Formation) are sandwiched between lower and upper platform carbonates (Pickelhaube and Dabie River Formations). The Hilda is unconformably overlain by the Numees Sequence, consisting of a widespread glaciogenic diamictite (Sendelingsdrif Formation) and a near-basal banded iron formation (Jakkalsberg Formation). A deep-water elastic unit, the Holgat Sequence, was laid down during the early stage of the lower Nama transgression.
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Bibliography: pages 128-143.
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Von Veh, M. 1988. The stratigraphy and structural evolution of the late Proterozoic Gariep belt in the Sendelingsdrif-Annisfontein area, northwestern Cape Province. University of Cape Town.