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将热分解元素分析仪(TC/EA)与同位素气体质谱仪(MS)连接起来,建立了TC/EA-MS在线连续流方法,分析了大别-苏鲁造山带超高压变质岩中矿物的水含量和氢同位素组成.采用分步加热方法,研究了石榴石中不同形式水(分子水和结构羟基)的含量和氢同位素组成.通过对若干典型露头超高压变质岩进行系统的矿物氢同位素和水含量测定,认识到在深俯冲板块折返过程中,超高压片麻岩能够比榴辉岩释放出更多的水.在榴辉岩和片麻岩接触带的降压脱水,释放的水会从片麻岩进入榴辉岩从而导致邻近片麻岩的榴辉岩发生显著的水化.通过测定榴辉岩中矿物最高水含量,得到石榴石和绿辉石在峰期超高压条件下所能溶解的最大水含量分别约为2500和3500 ppm.
The TC / EA-MS on-line continuous flow method was established by the combination of thermal decomposition elemental analyzer (TC / EA) and isotope mass spectrometer (MS), and the mineralogy of the minerals in the UHP metamorphic rocks of the Dabie-Sulu orogenic belt Water content and hydrogen isotope composition.The content and hydrogen isotope composition of different forms of water (molecular water and structural hydroxyl) in garnet were investigated by a step-by-step heating method.Through systematic hydrogen isotope analysis of several typical outcrop UHP metamorphic rocks And water content, it is recognized that ultra-high-pressure gneiss can release more water than eclogites during the reentry of deep-subducted slabs. In the step-down dewatering of eclogite and gneiss contact zones, the released water Will enter the eclogite from gneiss and cause significant hydration of the eclogite near the gneiss.Getalite and omphacite can be dissolved under peak high pressure conditions by measuring the maximum water content of the minerals in the eclogites The maximum water content is about 2500 and 3500 ppm, respectively.