Talk:Komatiite
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[edit] French Guyana komatiitic diamonds
It is worth discussing this first. For instance, the Dachine diamond occurrence is within a talc-schist, which is a metamorphosed ultramafic rock. It is therefore not sufficient to say that because the rock geochemically meets the criteria of a komatiite that it is a komatiite. For instance Magee and Taylor (1999) here argue that the Dachine talc-schist is actually probably a shoshonite occurrence. From my knowledge of the ultramafic dykes of Gympie, Australia, which were also shoshonites, these can look extremely similar to komatiites, especially when alteration strips away their LILE element enrichments in Ba, Rb, Sr, etc. So, I, for one, would like to see a definitive reference provided before we re-include the Dachine rocks as an example of a komatiite source rock for diamonds.
However, if it is a shoshonite, this makes for VERY interesting reading because shoshonites are much more widespread than kimberlites, komatiites or lamprites...so thanks whoever brought this to our attention!
Rolinator 04:19, 28 February 2006 (UTC)
