Just like Kim, Alessia, and Hypocentre, I’ve been having fun with the One Geology portal, which presents the first incarnation of the project to create the world’s first online, global, geological map. You can even download geological overlays for Google Earth, which is so cool that I’ll forgive the fact that the portal doesn’t yet work with Firefox 3, which has forced me to dust the electronic cobwebs off Internet Explorer*
Anyway, here’s the geology beneath my feet right now:
The circular green and pink area in the bottom right (north-east) corner is granite-greenstone basement which formed 3-3.1 billion (3000-3100 million) years ago. The different-coloured concentric bands surrounding this (starting with yellow, ending with orange) are the various units of the Witwatersrand Supergroup, a cratonic cover sequence which is the same age as the Pongola rocks that I’ve been studying during my time here; both sequences were probably originally deposited in a single basin, which has since been dismembered by later geological happenings. Gold-bearing conglomerates in the Witwatersrand – the source of 40% of all the gold ever mined – are the reason for Johannesburg’s existence. As you can see, the University (and my current abode) are located – appropriately enough – on top of the lowest unit of the Witwatersrand. Younger sequences (by South African standards – virtually every unit in this image is more than 2.3 billion years old) can be seen around the western and southern edges.
Given that these are still the very early days of this project, I’m getting very excited about what geological goodies we’ll see online in the future.
*If that turns your stomach, according to Hypocentre the Flock social browser, which is based on Firefox 2, also works.
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