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中国大陆科学钻探工程预先导1孔(CCSD-PPH1)位于大别—苏鲁超高压变质带东段的江苏东海县,孔深为432 m,其岩心为一套变质表壳岩、花岗质片麻岩和镁铁-超镁铁质侵入岩。它们经历了超高压变质作用和随后的角闪岩相退变质作用。这些岩石中存在四类流体包裹体:①中高盐度CaCl_2-NaCl-H_2O包裹体(Ⅰ型),宿主为榴辉岩中的石榴子石、绿辉石和蓝晶石石英岩中的蓝晶石,可能代表了峰期变质流体;②H2O-CO_2(±N_2)-NaCl±固体的包裹体(Ⅱ型),宿主为榴辉岩中的石英和蓝晶石石英岩中的蓝晶石,可能为超高压岩石折返和退变质期间带入岩石的流体;③中—低盐度水溶液包裹体(Ⅲ型),产于蓝晶石石英岩、榴辉岩和片麻岩中。蓝晶石石英岩中的包裹体是部分继承了俯冲阶段变沉积岩脱水-脱挥发分流体;榴辉岩和片麻岩中的中-低盐度水溶液包裹体主要是角闪岩相退变质期间或更晚期捕获的;④中-低密度的富CO_2包裹体(Ⅳ型),沿蓝晶石石英岩石英中的(切)穿颗粒裂隙分布。根据包裹体显微测温数据,从Ⅰ型包裹体的等容线得到的压力值大大低于根据矿物温压计获得的压力。这表明大多数Ⅰ型包裹体的组成和密度在捕获后均发生了不同程度改变。这些变化包括渗漏、部分爆裂和流体-岩石相互作用等。流体包裹体研究也表明本区超高压变质作用峰期流?
The pre-pilot 1 hole (CCSD-PPH1) of the Chinese Continental Scientific Drilling Project is located in Donghai County, eastern part of the Dabie-Sulu UHP metamorphic belt with a hole depth of 432 m. The core of the CCSD-PPH1 core is a set of metamorphic crustal and granitic flax Rock and mafic-ultramafic intrusive rock. They underwent UHP metamorphism and subsequent metamorphism of amphibolite. There are four types of fluid inclusions in these rocks: ① medium-high salinity CaCl_2-NaCl-H_2O inclusions (type Ⅰ) hosted by garnet, omphacite and kyanite quartzite in eclogites , Probably representing the peak metamorphic fluid; ② inclusions of H 2 O-CO 2 (± N 2) -NaCl ± solids (type Ⅱ) hosted by quartz and kyanite quartzite from eclogites probably as Fluids that were brought into the rock during the reenforcement and retrogressive metamorphism of the ultrahigh-pressure rocks; and ③ medium- low salinity aqueous inclusions (type III), which are produced in the kyanite quartzite, eclogite and gneiss. The inclusions in the kyanite quartzite partially inherit the dewatering-devolatilization fluid from the subducted sedimentary rocks. The inclusions in the eclogites and gneisses are mainly inclusions of amphibolite during the metamorphism Or more late-captured; ④ medium-low-density CO 2 -rich inclusions (type IV) distribute along the (cut) through grain fissures in the kyanite quartzite. According to the inclusions microscopic temperature data, the pressure values obtained from the isopotential line of type I inclusions are much lower than those obtained from mineral thermometers. This indicates that the composition and density of most Type I inclusions varied to varying degrees after capture. These changes include seepage, partial bursts and fluid-rock interactions. Fluid inclusions study also shows that the region metamorphic peak of ultrahigh pressure flow?