Naked Science Forum

Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: rosnathan on 04/10/2008 04:27:32

Title: From where do Diamonds get their Carbon?
Post by: rosnathan on 04/10/2008 04:27:32

Where do diamonds get their carbon? Is the source biologic, or strictly inorganic (that is from the rocks), or a combination?

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Title: Re: From where do Diamonds get their Carbon?
Post by: Bass on 04/10/2008 19:26:07

Depends.
(How's that for a typical answer from a geologist?)

Diamonds are classified according to their source rock into peridotitic and eclogitic suites.  Peridotitic diamonds are composed primarily of primordal (inorganic) carbon, as shown by their relatively heavy carbon isotope composition.  Carbon isotopes for eclogitic diamonds have a more widespread distribution, suggesting they are partially formed from organic carbon derived from subducting slabs.

For more detailed information, see:
The origin of cratonic diamonds – constraints from mineral inclusions
T. Stachel, J.W. Harris
http://research.eas.ualberta.ca/drg/Cratonic_Diamonds.pdf