Three-dimensional Fe speciation of an inclusion cloud within an ultradeep diamond by confocal µ-X-ray absorption near edge structure: evidence for late stage overprint.
Anal Chem
; 83(16): 6294-9, 2011 Aug 15.
Article
em En
| MEDLINE
| ID: mdl-21707095
ABSTRACT
A stream of 1-20 µm sized mineral inclusions having the negative crystal shape of its host within an "ultra-deep" diamond from Rio Soriso (Juina area, Mato Grosso State, Brazil) has been studied with confocal µ-X-ray absorption near edge structure (µXANES) at the Fe K and Mn K edges. This technique allows the three-dimensional nondestructive speciation of the Fe and Mn containing minerals within the inclusion cloud. The observed Fe-rich inclusions were identified to be ferropericlase (Fe,Mg)O, hematite and a mixture of these two minerals. Confocal µ-X-ray fluorescence (µXRF) further showed that Ca-rich inclusions were present as well, which are spatially separated from or in close contact with the Fe-rich inclusions. The inclusions are aligned along a plane, which most likely represents a primary growth zone. In the close vicinity of the inclusions, carbon coated planar features are visible. The three-dimensional distribution indicates a likely fluid overprint along an open crack. Our results imply that an imposed negative diamond shape of an inclusion alone does not exclude epigenetic formation or intense late stage overprint.
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MEDLINE
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En
Ano de publicação:
2011
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Article