On a recent trip to Gauteng I went to visit the Tswaing crater, one of the most spectacular yet least known tourism sites in South Africa, which lies about 40 kilometres north of Pretoria.
On a recent trip to Gauteng I went to visit the Tswaing crater, one of the most spectacular yet least known tourism sites in South Africa, which lies about 40 kilometres north of Pretoria.
The crater is large – about 1.2km in diameter and 100 metres deep – and was created in an instant about 220 000 years ago when a rocky meteorite slammed into the earth.
Today it is not that easy to find Tswaing because you have to drive through poorly sign-posted roads in Soshanguve, but it is well worth the effort.
The meteorite that blasted out the crater was made of a type of stone called chondrite and was between 30m and 50m wide, or about half the size of a soccer field.
The name Tswaing means Place of Salt in Setswana, and refers to a saline lake that covers the floor of one of the best-preserved meteorite impact craters in the world. There is evidence to suggest that salt was mined from the lake as far back as 100 000 years ago.
The water is brackish because it is fed by underground springs and rainwater which bring minerals into the lake, but as there is no outlet, the water does not get washed out. As the water evaporates, it leaves the minerals behind in the lake.
Until quite recently there was a running dispute about the origin of the crater. Some scientists thought it might have been volcanic while others argued that it was caused by a meteorite but in 1990 experts took core samples from a borehole proving conclusively that it is indeed an impact crater. Astronomers have calculated that the meteorite was probably travelling at about 40 000km per hour and that the release of kinetic energy would have been about 500 times greater than the atomic bomb that destroyed Hiroshima in 1945.
It is believed that the shock wave from the blast of the impact would've killed virtually all living things within a radius of at least 20km.
The Tswaing Crater is almost the same size as the famous Barringer Crater in the United States but does not appear to have many visitors. My family and I were at the site for about two hours during school holidays and we didn't encounter any other visitors in the area.
It is possible to enter the site by car and then drive to within 50m of a viewpoint, but there's also an option to do a 7.2km hike to the bottom of the crater.
If you decide to make the trip, make sure you take along all you need in terms of snack food – there is no cafe or souvenir shop.
Although Tswaing is not currently listed as a World Heritage Site, the South African government has engaged with UNESCO about including it on the list.
