Three-Dimensional Fe Speciation of an Inclusion Cloud within an Ultradeep Diamond by Confocal 渭-X-ray Absorption Near Edge Structure: Evidence for Late Stage Overprint

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• 作者：Geert Silversmit ; Bart Vekemans ; Karen Appel ; Sylvia Schmitz ; Tom Schoonjans ; Frank E Brenker ; Felix Kaminsky ; Laszlo Vincze
• 刊名：Analytical Chemistry
• 出版年：2011
• 出版时间：August 15, 2011
• 年：2011
• 卷：83
• 期：16
• 页码：6294-6299
• 全文大小：898K
• 年卷期：v.83,no.16(August 15, 2011)
• ISSN：1520-6882

文摘

A stream of 1鈥?0 渭m sized mineral inclusions having the negative crystal shape of its host within an 鈥渦ltra-deep鈥?diamond from Rio Soriso (Juina area, Mato Grosso State, Brazil) has been studied with confocal 渭-X-ray absorption near edge structure (渭XANES) 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 渭-X-ray fluorescence (渭XRF) 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.