A question for #geology mastodon: After a visit to the Derwent Pencil Museum this weekend as the nearest the group had to a geologist I was asked why do we get #graphite in the Lake District instead of #diamond?
The best I could come up with was that the volcanoes in the Lakes were smaller and cooler (?) than the ones in say S. Africa.
@ianturton Basically a pressure thing. Diamond will be stable form of elemental carbon in the Earth below 150 km or so (+- a bit depending on how cold or hot the rocks at depth are). It's probably quite common down there, but we only get to see it if it comes up really fast. Otherwise it turns back to graphite en route. Such speedy, deep magmas are very rare, hence so are diamonds.... /more
@FaithfullJohn@ianturton learning about kimberlite and the diamond pipes was one of the many mind blowing parts of my recent John McPhee geology book binge. Incredible stuff
@ianturton@FaithfullJohn he wrote four separate volumes but they're compiled in the single large Pulitzer winning work Annals of the Former World. I cannot possibly recommend it highly enough. I read it from the library and immediately bought a copy - the highest form of praise for any book. McPhee is a writer of stunning skill and his command of the material is profound. He conveys geology as a fascinating, dynamic and incredibly engaging field. One of the very greatest nonfiction works IMO.
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