Dondong Fm
Type Locality and Naming
Restricted to the southwestern Kalahari Basin in Botswana. Lower formation in Stormberg Gr in Kalahari Basin (SW)
Synonym:
Lithology and Thickness
A classic "red bed" sequence dominated by reddish-brown to maroon mudstones and siltstones, intercalated with lenses of fine- to medium-grained fluvial sandstones.
Relationships and Distribution
Lower contact
Unconformably overlies the Beaufort Gr equivalents in the Central region (such as the Kwetla Fm or Boritse Fm), and Kule Fm in SW part marking a significant regional hiatus that reflects the mid-Triassic unconformity seen across much of Gondwana.
Upper contact
Conformably to paraconformably overlain by the massive aeolian desert sandstones of the Nkalatlou Fm (Clarens Fm equivalent).
Regional extent
Restricted to the southwestern Kalahari Basin in Botswana. Because it is largely covered by modern Cenozoic Kalahari Group sands, it is primarily known from borehole data and isolated subcrop mapping. Southwestern part of the Kalahari Karoo Basin, Botswana. Lower/Middle Stormberg Gr equivalent. It is the direct regional chronostratigraphic equivalent of the Elliot Fm (and potentially the uppermost Molteno Fm) in the Main Karoo Basin (South Africa), and the Mosolotsane Fm in the central/eastern Kalahari Basin of Botswana.
GeoJSON
Fossils
Age
Depositional setting
Continental, semi-arid fluvial and floodplain environments.
Additional Information
The Dondong Fm is a crucial lithostratigraphic unit for understanding the Triassic-Jurassic boundary and the progressive aridification of southern Africa prior to Gondwanan breakup.