Vredefort Dome

The meteorite impact that happened in the Free State made a crater that was about 300 km wide (from Johannesburg to Welkom!). This is the biggest meteorite impact that geologists have yet found on Earth and it is nearly twice as big as the impact that killed the dinosaurs 65 million years ago. This makes it a site of great importance for scientists. It is also the oldest impact crater that has been found on Earth. It is mainly for these reasons that it has been made a World Heritage Site.

Over many decades, geologists from South Africa and other parts of the world have been studying the broken and melted rocks around Parys and Vredefort to understand this Vredefort Impact Even. This is what they have found:

1. The meteorite impact happened about 2023 million years ago, at a time when there were no people or even animals of plants like we see today. The only living thing was a type of algae, like the green slime seen in dams today.

2. To make a crater 300 km wide, the meteorite must have been about 10 km across (as big as a mountain) and travelling at more than 10 km per second (36 000 km/h!).

3. The Vredefort Dome is only the central part of the impact crater. It is called a dome because the rock layers were bent into the shape of an upside-down bowl 90km across by the impact.