Beaufort Gr
Type Locality and Naming
Main Karoo Basin (SE), Main Karoo Basin (Western Foredeep), Main Karoo Basin (Eastern/Northern Forebulge), Waterberg Basin, , Kalahari Basin (SW), Kalahari Basin (Central), Kalahari Basin (NE), Mid-Zambezi Basin, Ellisras Basin, Tshipise Basin, Tuli Basin, Save Basin, Morondava Basin (Madagascar), Metangula Basin (Mozambique), Luangwa Basin (Zambia), Ruhuhu Basin (Tanzania), Congo Basin (Lukuga-DR Congo), South Africa
Synonym:
Lithology and Thickness
Dominated by alternating sequences of sandstones and mudstones (fining-upward fluvial cycles) with notable red and purple-grey coloring.
In the type-basin, the group is massive and formally subdivided into several formations spanning the Permo-Triassic boundary- Middle to Late Permian: Abrahamskraal Fm, Koonap and Middleton Fm, and Balfour Fm (fluvial mudstones and sandstones). Early to Middle Triassic: Katberg Fm (fluvial sandstones) and Burgersdorp Fm (fluvial mudstones and sandstones).
Relationships and Distribution
Lower contact
Conformably overlies the shallow marine/coastal deposits of the uppermost Ecca Gr (e.g., the Waterford Fm in the Main Karoo Basin) marking the end of marine influences.
Upper contact
Unconformably overlain by the basal units of the Stormberg Gr (e.g., the Molteno Fm or Escarpment Grit). This contact is typically marked by a major regional stratigraphic hiatus during the Middle Triassic (Ladinian).
Regional extent
Extremely widespread; forms the dominant terrestrial fossiliferous sequence across the Main Karoo Basin and correlates to almost all other south-central African Karoo basins. Madagascar (Morondava Basin): The Sakamena Gr represents the entirety of Beaufort deposition. The Lower Sakamena corresponds to the Late Permian, while the Middle and Upper Sakamena represent the Early to Middle Triassic. Ruhuhu Basin (Tanzania): Ruhuhu Fm (lacustrine Kazanian), Usili Fm (fluvial Tatarian containing Dicynodon), and the Manda Beds (Scythian–Anisian sandstones containing Cynognathus zone fossils). Luangwa & Mid-Zambezi Basins: The Middle and Upper Madumabisa mudstones. Congo Basin (DRC): Referred to as the "Transition beds" (red and green mottled mudstones with basal conglomerates). Springbok Flats (South Africa): The Irrigasie Fm, which spans the Beaufort-Stormberg boundary into the Early Jurassic.
GeoJSON
Fossils
World-renowned for its continuous terrestrial tetrapod fossil record, heavily utilized for global biostratigraphic zonation (e.g., Dicynodon, Cynognathus, Lystrosaurus, Tropidostoma, and Cistecephalus Assemblage Zones) (Section 5.3).
Age
Depositional setting
Entirely terrestrial, dominated by meandering and braided fluvial rivers, floodplains, and shallow lacustrine environments. Represents the "overfilled" stage of the Karoo retroarc foreland system, where sediment supply completely outpaced basin subsidence (Figure 2).
Additional Information
The Beaufort Gr is critical for recording terrestrial life spanning the Permo-Triassic extinction event.