The structural and stratigraphic setting of the Rosh Pinah zinc-lead deposit within the Gariep trough

Abstract

Abstract provided by author:

During regression banded iron formations were deposited in shallow depressions and the glaciogenic Numees Sequence diamictites were deposited unconformably above the Hilda Sequence and iron formations. These in turn are overlain by the deep-water clastics of the Holgat Sequence. The Witputs Sequence, which unconformably overlies the Numees Sequence along the basement in the east is seen as a proximal shallow water equivalent of the distal Holgat Sequence

The mass flow Kaigas Formation diamictites and volcaniclastics of the Rosh Pinah Formation were subsequently deposited in locally developed grabens. Syn-sedimentary ore beds of hydrothermal origin (including Rosh Pinah orebodies) were precipitated on the sea floor while reef carbonates formed along the coast line during the final stages of transgression. These sediments were eventually covered by a marginal marine clastic and carbonate facies with widespread intrusion of basic sills and dykes following uplift of the craton. These rocks are here grouped within the Rosh Pinah Formation

During the sea floor spreading stage of continental evolution the clastic-carbonates of the Hilda Sequence were deposited in a shallow to moderately deep-water environment. The Wallekraal conglomerates were deposited as local submarine fans with minor debris flows and are overlain by the Dabie River Formation carbonates