Kweneng Fm
Type Locality and Naming
Named after the Kweneng District in Botswana. As it is largely blanketed by the Cenozoic sands of the Kalahari Group, it was primarily defined from stratigraphic and groundwater boreholes by the Botswana Geological Survey, with very rare local surface exposures (e.g., south of Letlhakeng). Middle formation in Ecca Gr in Kalahari Basin (Central).
Synonym:
Lithology and Thickness
Predominantly an arenaceous (sandy) succession. It is characterized by massive, frequently cross-bedded, medium- to coarse-grained feldspathic sandstones (arkose), with occasional pebble beds and basal conglomerates. It also contains subordinate intercalated dull coal bands and carbonaceous, coaly mudstones.
Relationships and Distribution
Lower contact
Typically overlies the finer-grained, pro-delta carbonaceous mudstones and siltstones of the Bori Fm (Lower Ecca equivalent).
Upper contact
Conformably or transitionally overlain by the finer-grained, coal-rich sequence of the Boritse Fm (Upper Ecca equivalent).
Regional extent
Widespread across the subsurface of the central, southern, and eastern sub-basins of the Kalahari Basin in Botswana.Middle Ecca Gr equivalent. It chronostratigraphically correlates with the Kamakwe Fm in some Botswana sub-basins, and with the lower-to-middle arenaceous successions of the Ecca Gr (such as the Vryheid Fm) in the Main Karoo Basin of South Africa.
GeoJSON
Fossils
Age
Depositional setting
Fluvial to deltaic environments. The Kweneng Fm represents a major prograding delta body and braided river system that advanced over the deeper-water pro-delta muds of the underlying Bori Formation.
Additional Information