(Above) Cross-section of the Tswaing crater modified after
Brandt, D., (1994), Brandt & Reimold (1999), Partridge & Reimold
(1990). The Tswaing crater has a simple bowl shape with a 1.13
km diameter. The outer rim is composed of shattered rock called
breccia and is elevated nearly 60m above the surrounding plains.
Most of the original ejecta blanket has been eroded away,
however numerous large granitic blocks can be found out to
hundreds of meters from the crater rim. Geology of Tswaing
Igneous Rocks: The most common rock type at the Tswaing crater
and in the surrounding region is the Nebo Granite. The Nebo
Granite is part of the Bushveld complex - a large layered
igneous intrusion. The Bushveld itself is a geological novelty,
consisting of several vertical kilometers of layered magmatic
rock which extends horizontally for several hundred kilometers.
The 2.06 billion year-old Bushveld complex is also one of the
world's largest sources of platinum group metals. Various small
intrusions and dykes also cut into