Thabala Fm
Type Locality and Naming
Named after the village of Tlhabala in the Central District of Botswana. It is primarily known from extensive coal and groundwater boreholes, with very limited, deeply weathered surface exposures. Included in Beaufort Gr in Kalahari Basin (NE).
Synonym:
Lithology and Thickness
A thick sequence of massive, non-carbonaceous claystones. It is composed of pale grey, green, yellowish, and reddish-purple to maroon mudstones and calcareous siltstones, with minor lenses of very fine-grained sandstone. The stark lack of carbonaceous (coaly) material is its key distinguishing feature from the underlying Ecca units.
Relationships and Distribution
Lower contact
Conformably and transitionally overlies the carbonaceous, coal-bearing fluvio-deltaic rocks of the upper Ecca Gr equivalents (such as the Boritse Fm or the Serowe Fm/Morupule Fm, depending on the specific sub-basin).
Upper contact
Unconformably overlain by the terrestrial red beds of the Mosolotsane Fm (Stormberg Gr equivalent). This sharp upper contact represents the major mid-Triassic regional depositional hiatus (unconformity) observed across southern Africa.
Regional extent
Widespread across the subsurface of the eastern, central, and northern sub-basins of the Kalahari Basin in Botswana. Beaufort Gr equivalent. It chronostratigraphically correlates with the Kwetla Fm (southern Botswana), the Kule Fm (southwestern Botswana), and the lower Beaufort Gr (Adelaide Subgroup) in the Main Karoo Basin of South Africa.
GeoJSON
Fossils
Age
Depositional setting
Expansive, low-energy terrestrial environments.
Additional Information