As you might have noticed, my blogging has been a little thin on the ground recently, which means I have been remiss in pointing you to some sterling posts from fellow All-geo blogger Simon Wellings, who is writing a whole series exploring the geology of mountains, with a focus on the Himalayas and the Tibetan plateau. As he explains, plate tectonics is often not a good model for deformation on continents, and of the many models that have been suggested and processes that have been proposed to explain how it all works, perhaps the most mind-bending is “channel flow“, where the middle regions of the crust are warmed and weakened as a plate thickens during an orogeny, then squeezed out sideways into neighbouring regions like toothpaste. As Simon’s most recent post explains, this process appears to have occurred beneath the Tibetan Plateau: driven by rapid erosion at the surface, channel flow has transported deeply buried rocks 200 km sideways and 20 km upwards to be exposed in the Himalayas. The peak of Everest may be stupendously uplifted marine carbonates, but the rocks that make up the slopes beneath have been on an even more extreme tectonic adventure. The Geology of Mount Everest comes complete with many fabulous photos taken by the author himself; the fact that Simon was in a position to do so makes me swoon with jealousy. Check it out.
Ooh. Click image for more pretty mountains, courtesy of Simon Wellings.
