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初步的岩相学和冷热台显微测温表明,CCSDHP-UHP岩石中石英脉和后期碳酸盐脉中含有3种流体包裹体:盐水溶液(NaCl-H2O)包裹体(Ⅰ类)、NaCl-CaCl2-H2O(Ⅱ类)和N2-CH4纯气相(Ⅲ类)包裹体,其中Ⅰ类盐水溶液包裹体可进一步分为中高盐度盐水溶液包裹体(Ia)、中等盐度盐水溶液包裹体(Ib)和低盐度盐水溶液包裹体(Ic),而Ⅲ类为CCSD中首次发现;Ia、Ib和Ⅱ型流体包裹体主要以原生或假次生形式赋存在榴辉岩的石英脉或石英颗粒中,在角闪岩相的片麻岩及其石英脉中均未观察到,显示它们可能主要被捕获于榴辉岩的减压重结晶或退变质阶段,而Ic型包裹体分布广泛,表明其主体可能是在超高压变质岩折返过程的最晚阶段捕获的;N2-CH4纯气相包裹体均为原生包裹体,主要呈孤立和小群状与Ia和Ib类包裹体分布于榴辉岩中条带状石英脉中,可能主要是在高压-超高压榴辉岩相变质条件下被捕获的;CCSD榴辉岩中石英脉的主体形成于板块折返有关的减压重结晶和退变质,而片麻岩中石英脉则主要来源于角闪岩相及其后期退变质作用;榴辉岩和片麻岩中石英脉流体包裹体的组成和地球化学特征存在明显区别,但它们各自相似于其寄主岩石中的石英颗粒中包裹体,说明CCSD中HP-UHP岩石在板块折返过程中释放出的变质流体没有经过大规模的迁移。
Preliminary petrographic and microscopic observations of hot and cold stations show that there are three kinds of fluid inclusions in quartz vein and later carbonate vein in CCSDHP-UHP rock: saline-H2O inclusions (class I) Inclusions of NaCl-CaCl2-H2O (type II) and N2-CH4 pure gas (type III) inclusions, of which type I brine inclusions can be further divided into moderate-high salinity brine inclusions (Ia), medium salinity brine (Ib) and low salinity brine inclusions (Ic), while the type III is the first discovery in CCSD. The fluid inclusions of type Ia, Ib and II mainly exist in the quartz vein of eclogites in primary or secondary forms Or quartz grains were not observed in the amphibolite facies gneisses and their quartz veins, indicating that they may be mainly captured in the stage of depressurized recrystallization or retrogressive metamorphism of eclogites, while the distribution of type Ic inclusions The results show that the main body may be captured at the latest stage of the UHP metamorphic rocks’ reentry process. The pure gaseous inclusions in N2-CH4 are all primary inclusions, mainly in the form of isolated and small groups with Ia and Ib inclusions Among the banded quartz veins in the eclogites, they may be mainly trapped under high-pressure-high-pressure eclogite facies metamorphism . The main body of quartz vein in CCSD eclogite is formed by decompression recrystallization and retrogressive metamorphism related to the plate reentry. The quartz vein of gneiss is mainly derived from amphibolite facies and retrogressive metamorphism. Eclogite The composition and geochemical characteristics of fluid inclusions of quartz veins in gneisses are obviously different, but they are similar to the inclusions of quartz grains in host rocks, indicating that the HP-UHP rocks in CCSD are released during plate folding Of the metamorphic fluid has not been large-scale migration.