Aeolian Sandstone Fm
Type Locality and Naming
Save Basin. Named after the picturesque town of Clarens in the eastern Free State, South Africa, which is surrounded by spectacular cliffs of this rock. It was originally named the "Cave Sandstone" by early pioneer geologists because its softer lower layers frequently weather to form deep rock overhangs and caves (which famously host extensive San rock art). The South African Committee for Stratigraphy (SACS) formally renamed it the Clarens Formation in 1980. In literature and borehole logs, it is frequently described generically as the "aeolian sandstone formation." Upper formation in Stormberg Gr
Synonym: Cave Sandstone (obsolete formal name),
Lithology and Thickness
A massive, highly uniform, fine-grained, and well-sorted arenaceous (sandy) succession. It is characteristically pale—ranging from cream, white, and pale-yellow to pale-pink. The absolute hallmark of this formation is the presence of gigantic, large-scale planar cross-bedding indicating wind-blown deposition. Thickness varies significantly: ranging from roughly 100 to 140 meters in the Ellisras and Springbok Flats basins, and swelling up to 300 meters thick in the Main Karoo Basin (Lesotho highlands).
Relationships and Distribution
Lower contact
Conformably and transitionally overlies the red mudstones of the Elliot Fm (Main Karoo), Lisbon Fm (Ellisras), Irrigasie Fm (Springbok Flats), or the Bosbokpoort Fm (northern basins). Oasis Sandstone and Limestone Fm (Save Basin).
Upper contact
Unconformably to conformably overlain (and sometimes distinctly interfingered at the very top) by the massive continental flood basalts of the Karoo Large Igneous Province (e.g., the Drakensberg Gr, Letaba Fm, or Springbok Flats Fm).
Regional extent
Extremely widespread across southern Africa. It forms the prominent, sheer, pale cliffs that cap the escarpments of the Drakensberg mountains. It is the direct regional chronostratigraphic equivalent of the Ntane Sandstone Fm (Botswana), the Forest Sandstone Fm (Zimbabwe), and the Etjo Sandstone Fm (Namibia).
GeoJSON
Fossils
Age
Depositional setting
A massive, hyper-arid continental erg (sand sea) environment.
Additional Information