Tags: AfricaArray

AfricaArray Geophysical Field School – Day 1, Vredefort Dome

I am currently attending the AfricaArray field school, hosted by [http://wits.ac.za](Wits University). The first day was a relaxed one to allow for the international students to recover from jetlag. Accordingly, we wandered off to visit the Vredefort Dome. This is one of the largest, and the oldest impact structures in the world, so we are very lucky that we can wander around it. It is also a UNESCO world heritage site. This is a world famous site and it was good to get an over view of the area. We started by getting an overview of the area, and the basic geology. Some of the most significant evidence is the presence of pseudotachylite within the basement granites of the Witwatersrand Basin. These formed under frictional melting due to the impact causing nearby rocks to move extremely rapidly. These are spectacularly exposed in some of the quarries in the area: These quarries are abandoned now, since the current fashion is for the use of very fine-grained, black facing stone, rather than textured rock. After that, we stopped next to the Vaal River for lunch, which was pretty idyllic. The work did not stop, since we worked out that the quartzite rocks […]