Quote:
Originally Posted by geonuc
......But I don't think we have a real good picture of mantle dynamics yet.
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I'd agree with that, most of my geology was learnt in the late '70s, one of my text-books still had mountains forming from subsiding geosynclines!
I had a look at Richard Fortey's 'The Earth' last night and that section is full of 'it appears that' and 'it is believed that'.
I think there is a problem with diamonds forming 150km+ below the crust so mantle plumes are the only mechanism capable of lifting them to/towards the surface, but you are right in saying they wouldn't be formed where the mantle plumes form.
As diamonds go I'd like this one...
http://news.bbc.co.uk/1/hi/sci/tech/3492919.stm (38kb) (although it would devalue the market a little).