西南天山俯冲带超高压变质流体与岛弧岩浆成因

The purpose of this project is to do the petrogenesis of UHP metamorphic fluids of eclogites, metapelites and serpentinites in southwestern Tianshan, China. The composition, characteristics and transformation of UHP metamorphic fluids in eclogites, metapelites and serpentinites will be studied according to the studies of phase petrology. The mechanism and formation of UHP metamorphic fluids will be established on the basis of trace element mobility during the ultrahigh pressure metamorphism. This study will focus on the effect of UHP metamorphic fluids on the formation of arc magmatism on the basis of the coeval arc volcanic rocks. Furthermore, the essential relationship between subduction-zone metamorphism and magmatism will be discussed deeply. This project is very significance to set up the mechanism and transmission of UHP metamorphic fluids in the cold subduction zone, and to understand the petrogenesis of arc magmatic rock.

该申请拟对新疆西南天山洋壳深俯冲超高压变质的榴辉岩、泥质片岩和蛇纹岩开展深入的流体作用岩石学研究工作。在变质岩相平衡石学研究基础上，确定超高压变质过程中流体的组成、性质和运移方式，确立微量元素在超高压变质过程中的活动性和迁移规律，建立冷俯冲带超高压变质流体形成和演化机制。并结合岛弧火山岩成因岩石学和地球化学研究，探讨俯冲带变质流体对岛弧岩浆的形成与演化的影响和贡献，从而建立俯冲带超高压变质作用与岛弧岩浆作用之间的本质联系。该项研究对于建立冷俯冲带超高压变质过程中流体形成机理和运移机制，探讨岛弧岩浆的成因都具有重要意义。

该项目对新疆西南天山洋壳深俯冲超高压变质的榴辉岩、泥质片岩和蛇纹岩开展深入的以变质流体作用为主线的岩石学研究工作。在变质岩相平衡石学研究基础上，确立了超高压变质过程中的榴辉岩、泥质片岩和蛇纹岩的变质演化、峰期矿物组合和变质温压条件以及变质时代，结合低压高温变质带中有关岛弧岩浆和S型花岗岩的研究，建立了西南天山造山带的构造演化模式；通过高温高压实验岩石学研究，确立了MORB体系中出现超高压变质矿物组合可能的流体组成和性质，探讨了水流体和微量元素在超高压变质过程中的活动性和变化，为建立俯冲带超高压变质作用与岛弧岩浆作用之间的本质联系奠定了基础。