Based on stratigraphic position, lithostratigraphic and biostratigraphic correlations,[3] palynological analyses, and other means of geological dating, the Beaufort Group rocks are considered to range between Middle Permian (Wordian) to Early Triassic (Anisian) in age.
[4][5] During the period when sedimentation of the Beaufort Group rocks took place, the Ecca sea had retreated to the northeastern Karoo Basin.
The continuation of mountain-building and erosion from the growing Gondwanide mountain chain and associated subduction created accommodation space for sediment deposition in the Karoo Basin.
The mudstones in the lower Beaufort Group are mainly greenish-grey to blueish-grey and gradually change to greyish-red, reddish-brown or purple in color.
The dominant presence of mudstones in the lower Beaufort Group represent tranquil depositional settings such as overbank or floodplain facies associations.
This is either due to erosion of the lowlands west of 24°E or sediment deposition in the western section of the Karoo Basin ceased at the end of the Permian.
[47][48][49][50][51] These assemblage zones are listed below: The Beaufort Group deposits also yield numerous insect, plant, and trace fossils.