The Rosenhof Member is part of the Lower Cambrian Fish River Subgroup of the Nama Group in southern Namibia (Groß Aub Formation). The sediments of the Nama Group are deposited in two basins, the northern Zaris Subbasin and the southern Witpütz Subbasin. Both are separated by the Osis Arch, a basement updoming (Germs, 1974; Grotzinger and Miller, 2008). While the basal two Nama subgroups are influenced by these two basins and their paleorelief, the uppermost Fish River Subgroup sediments overstep the Osis Arch and cover previous deposits with an unconformity. Deposits of the Fish River Subgroup are represented by Lower Cambrian shales and sandstones (e.g. Grotzinger and Miller, 2008).
The sandstones of the Rosenhof Member show distinct sedimentary patterns that allow the interpretation as fluvial deposits originating from the north (e.g. Geyer, 2005). They were deposited after the final collision of the Kalahari Craton (south) and the Congo Craton (north) that created the Damara Orogen. The latter is discussed as a major sedimentary source area for the studied deposits covering southern Namibia (Kalahari Craton). For this purpose, the Rosenhof Member was sampled and studied at various locations, covering occurrences from its northern outcrops until its most southern ones. This sample set allows the study of changes in the sedimentary pattern of a particular member over an area of about 300 km.
This talk presents sedimentary structures combined with heavy mineral analyses (U-Pb on zircon and apatite) and discusses possible sedimentary source areas, as well as sedimentary mixing and homogenisation.