Kalkkop
Key facts
- Country
- South Africa
- Diameter
- 640 m
- Age
- about 250,000 years
- Location
- 32.72° S, 24.43° E
A shallow, round hollow about 640 m across in the dry Karoo of the Eastern Cape, South Africa, partly filled with pale limestone deposits.
Kalkkop is a small impact crater about 640 m across in the semi-desert Karoo of the Eastern Cape, South Africa, near the town of Graaff-Reinet. Its name means 'lime head' in Afrikaans.
What can be seen. The crater is a shallow, round hollow with a low rim. It is partly filled with calcrete, a hard limestone deposit that forms in dry climates when lime in groundwater collects near the surface. The calcrete gives the crater its pale colour and its name.
What it hit. The impactor struck sandstones and mudstones of the Karoo Supergroup, laid down about 250 million years ago.
Proof of impact. The hollow was long thought to be volcanic or the result of other processes. In the 1990s scientists drilled through the fill and recovered breccia with quartz grains showing planar deformation features, confirming an impact.
Age. Dating of the calcrete and sediments filling the crater suggests it formed about 250,000 years ago.
Why it matters. Kalkkop is one of the youngest known impact craters in Africa. The impactor is unknown.
Visiting. The crater is on private farmland. Ask the landowner's permission before visiting.
Did you know?
Kalkkop means 'lime head' in Afrikaans.
The crater is partly filled with a pale limestone deposit called calcrete.
Drilling through the fill in the 1990s confirmed it was an impact crater.