The rock units on the farm belong to the Pretoria Group of the Transvaal Sequence. It consists largely of sedimentary rocks(shale, sandstone, etc.), and chemical sedimentation (i.e. dolomite, chert). On the eastern part of the farm, outcropping rocks consist of quartzitic sandstone and quartzite. Sedimentary textures are still visible in the rocks. From these textures it is possible to determine the direction in which the rivers responsible for the sandstone deposits flowed. The sandstone dips at a shallow angle (5°-10°) towards the west.
| Evidence exists of hardened riverbed in the main valley indicating the course of the river. Shallow sand deposits are also found. |
Further west, more or less where the stream is dividing the farm, shale units occur. These rocks are very fine grained and weathers quite easily so that they don’t outcrop as much. Still further west forming the higher topography, numerous dolerite dykes intruded the shales, showing some metamorphism (a closer look at the individual minerals in the rocks shows needle like textures indicating metamorphic recrystallisation). Towards the most north western border fence, outcropping gabbro occurs. Gabbro refers to a large group of dark, coarse-grained, intrusive igneous rocks formed when molten magna is trapped beneath the Earth’s surface and cooled into a crystalline mass.
Local and regional faults caused displacement of all the rock units. The best one visible is the one just north of the property forming a deep gorge-like topography.
