title: 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.
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.
authors.affiliation: X-ray Microspectroscopy and Imaging Research Group (XMI), Department of Analytical Chemistry, Ghent University, Gent, Belgium. Geert.Silversmit@UGent.be
authors.forename: Geert
authors.initials: G
authors.lastname: Silversmit
authors.forename: Bart
authors.initials: B
authors.lastname: Vekemans
authors.forename: Karen
authors.initials: K
authors.lastname: Appel
authors.forename: Sylvia
authors.initials: S
authors.lastname: Schmitz
authors.forename: Tom
authors.initials: T
authors.lastname: Schoonjans
authors.forename: Frank E
authors.initials: FE
authors.lastname: Brenker
authors.forename: Felix
authors.initials: F
authors.lastname: Kaminsky
authors.forename: Laszlo
authors.initials: L
authors.lastname: Vincze