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

Geert Silversmit*, Bart Vekemans, Karen Appel, Sylvia Schmitz, Tom Schoonjans, Frank E. Brenker, Felix Kaminsky, Laszlo Vincze

*Corresponding author for this work

Research output: Contribution to journalArticle

25 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)6294-6299
Number of pages6
JournalAnalytical Chemistry
Volume83
Issue number16
DOIs
Publication statusPublished - 15 Aug 2011
Externally publishedYes

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