Collaborative Research: Osmium Isotopes, PGE, and Trace Element Systematics in Kamchatka Sub-Arc Mantle: Implications for Slab-Mantle Interactions

9903234 Kepezhinskas来自堪察加亚弧地幔的捕虏体表现出不同的岩相学特征，这些特征归因于不同成分的板状流体在不同P-T条件下产生的不同程度的交代作用。这项研究将涉及50- 60个岩石学特征良好的捕虏体的地球化学分析，代表沿着和跨弧变化的交代堪察加岛弧地幔楔。Osisotope和PGE丰度测量将与主元素和亲石微量元素分析相结合，以表征板片俯冲过程中释放到地幔楔中的流体，并记录流体-地幔相互作用的过程。高度不相容元素与高度相容元素的组合使用将为这些过程提供独特的视角。此外，板幔相互作用过程中PGE的迁移程度和PGE分馏类型对地幔中不同的亲铁元素丰度模式的起源具有重要意义。

9903234KepezhinskasXenoliths from the Kamchatka sub-arc mantle exhibit diverse petrographiccharacteristics that have been attributed to variable degrees ofmetasomatism by slab fluids of diverse compositions, generated over a rangeof P-T conditions. This study will involve geochemical analyses of 50-60petrographically well-characterized xenoliths, representing along- andacross-arc variations in the metasomatized Kamchatka arc mantle wedge. Osisotope and PGE abundance measurements will be combined with major elementand lithophile trace element analyses to characterize the fluids releasedto the mantle wedge during slab subduction, and to document the processesof fluid-mantle interaction. The combined use of highly incompatibleelements with highly compatible elements will provide a unique perspectiveon these processes. In addition, the extent of PGE mobility and the typesof PGE fractionations that occur during slab-mantle interactions will haveimportant implications regarding the origin of variable siderophile elementabundance patterns in mantle from other tectonic settings.