Teekloof Formation

Geology

The Teekloof Formation overlies the Abrahamskraal Formation and is not capped by any other preserved sedimentation. Only East of 24ºE does the preservation of Beaufort Group rocks continue. There is no rock preservation in the western-southwestern portions of the Karoo Basin. It is unclear whether rock preservation there ceased in the Late Permian due to localized basinal tectonics, or if that rock material was preserved but later weathered away. The Teekloof Formation has five subdivisions or members which are listed below (from oldest to youngest):

• Poortjie Member - Correlates with the Pristerognathus Assemblage Zone
• Hoedemaker Member - Correlates with the Tropidostoma Assemblage Zone
• Oukloof Member - Correlates with the Cistecephalus Assemblage Zone
• Steenkampsvlakte Member - Correlates with the Daptocephalus Assemblage Zone
• Javanerskop Member - Correlates with the Daptocephalus Assemblage Zone

Lithologies

The sedimentary rocks of this formation are predominantly reddish or minor green mudstones that are either structureless, horizontally laminated, or medium to thickly bedded. Pedogenic and diagenetic carbonate nodules and also fossil gypsum rosettes occur in the mudstone deposits. Interbedded with the mudstone deposits are minor channel sandstones ranging from pale olive to greenish-grey in colour. The sandstones are fine to medium grained and preserve fining-upward sequences (e.g. from bottom to top: Massive, horizontally laminated, trough cross-bedded, and ripple cross-laminated sedimentary structures). In the uppermost sections of the Teekloof Formation, the Javanerskop Member contains ribbon-shaped, single storied sandstones. These sandstones in the uppermost sections contain numerous erosional surfaces lined with siltstone or mudstone pellet conglomerates.

Geologists consider the Teekloof Formation depositional environment to have been a floodplain facies association that underwent seasonal arid conditions and playa lake formation as indicated by the presence of fossil gypsum rosettes and carbonate nodules. The sandstone occurrences preserve evidence of deposition on point bars in a meandering river system. Seasonal waning flood level events are indicated by the fining upward sequences.