Kobe Fm
Type Locality and Naming
Kalahari Basin (SW). As with the overlying Kule and Otshe formations, it does not naturally outcrop and was formally defined from subsurface borehole cores by the Botswana Geological Survey.
Synonym:
Lithology and Thickness
Dominated by a thick sequence of dark grey to black carbonaceous shales, mudstones, and subordinate siltstones. It is further divided into Ncojane Member. It is the basal sandstone sequence of the Ecca Gr in Botswana, lying directly at the base of the mudrock-dominated Kobe Fm. The Ncojane Member consists of fine- to medium-grained sandstones.
Relationships and Distribution
Lower contact
Typically, conformably overlies the basal Ecca sandy/silty units (such as the Khuis Fm) or, where those are absent, rests directly upon the glaciogenic diamictites of the Dwyka Gr equivalents (Malogong Fm).
Upper contact
Conformably and transitionally overlain by the coarser-grained, coal-bearing fluvio-deltaic sequences of the Otshe Fm.
Regional extent
Widespread across the subsurface of the Gemsbok Sub-basin in southwestern Botswana. Middle Ecca Gr equivalent. It chronostratigraphically correlates with the Whitehill and Collingham Fm, and Tierberg Fm in the Main Karoo Basin of South Africa. Ncojane Member is the direct Botswana equivalent of the highly important Nossob Sandstone Member (which belongs to the Prince Albert Fm in Namibia/South Africa). Because of this direct correlation across the border, some modern hydrogeological reports for the Stampriet Artesian Basin simply refer to the Ncojane unit as the "Nossob" or "Lower Kobe Sandstone."
GeoJSON
Fossils
Age
Depositional setting
Deep-water, low-energy, anoxic lacustrine or restricted inland sea environment.
Additional Information