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

来自堪察加弧下地幔的9903234克佩钦斯卡岩具有不同的岩相学特征，这归因于在一系列P-T条件下产生的不同成分的板岩流体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包体的地球化学分析，这些包体代表了交代的堪察加弧地幔楔形岩沿和跨弧的变化。同位素和PGE丰度测量将与常量元素和亲岩石微量元素分析相结合，以表征在板块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。高度不相容的元素和高度相容的元素的组合使用将提供对这些过程的独特视角。此外，在板幔相互作用过程中PGE活动性的程度和PGE分馏的类型将对其他构造背景下地幔中不同的亲铁元素丰度模式的起源具有重要的意义。

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.