Petrogenesis of Diamonds and Their Host Xenoliths

点击翻译按钮获取中文摘要

9725885TaylorThis research involves an integrative approach to the study of the age, formation and evolution of diamonds and their host xenoliths form Yakutia, Siberia. Three carefully chosen diamond-bearing eclogite xenoliths and two large diamonds (cut into 10 carat plates) will be used as recorders of the evolution of the Earth's mantle. Mineral inclusions within diamonds are considered reliable indicators of mantle conditions during diamond formation because these inclusions were isolated from post-diamond formation mantle processes. Since mineral inclusions within a single diamond can be variable it is important to document how the inclusions fit within the growth history of the diamond. This research will provide the first comprehensive geochemical and petrologic study of inclusions within diamonds that links the chemical characteristics to the diamond growth history. This will involve cathodoluminescence and C and N isotopic analyses of the diamonds prior to the study of the xenoliths and inclusions. The xenoliths will be imaged by X-ray computed tomography, prior to disaggregation, to examine the diamond-host textural relationships. Mineral inclusions and host xenolith minerals will be studied by a variety of techniques: major and trace element and O isotopic analyses of silicates; and Re-Os and S isotopic analyses of sulfides. This integrated study of diamonds, inclusion minerals and host xenoliths will make a significant contribution to the knowledge of mantle conditions necessary for diamond formation, and the evolution of the mantle beneath the Siberian Platform.