An Investigation of Fluid-Rock Interaction During Subduction Zone Metamorphism

CO2-H2O对30 km深度的不渗透性应是 等温线下降的直接结果， 物质沿着俯冲带向下的主动运输。 流体相 在这种环境下，分离应该有一些重要的 热、机械和变质的后果 俯冲带的发展，然而， 流体不渗透性控制岩石学过程的程度 在高压下 将特别注意 确定是否有小规模的蓝片岩和 绿片岩、蓝片岩和榴辉岩组合的形成， 流体非均质性的产生和保存， 这种不均匀性可能由流体相分离引起。 采用的方法是（1）利用矿物相平衡， 计算相邻层之间的（H2O）和（CO2）比率， 在相类型内和跨相边界，（2）至 直接从多个代确定流体成分 流体包裹体，（3）模拟岩石的反应途径 在不混溶和超临界流体两种情况下。样品 要研究的是来自Ile上的相干高压蒸汽 德格鲁瓦，在陶恩窗口，在锡夫诺斯岛。 的 结果应提供更好的约束的组成， 流体在高压下存在，并导致更好的模型， 俯冲板块的挥发分

CO2-H2O immiscibility to depths of 30 km should be a direct result of the depression of isotherms that occurs during active transport of material down a subduction zone. Fluid phase separation in this environment should have a number of important consequences for the thermal, mechanical, and metamorphic development of subduction zones, yet the effect documenting the extent to which fluid immiscibility controls petrologic processes at high pressure. Particular attention will be paid to determining whether small-scale interlaying of blueschist and greenschist and blueschist and eclogite assemblages results from generation and preservation of fluid heterogeneities and whether such heterogeneities could be caused by fluid phase separation. The approach taken will be (1) to use mineral phase equilibria to calculate a (H20) and a (C02) ratios between adjacent layers both within facies types and across facies boundaries, (2) to determine fluid compositions directly from multiple generations of fluid inclusions, and (3) to model reaction pathways for rocks in both the immiscible and supercritical fluid regimes. Samples to be studied are from coherent high-pressure terranes on the Ile de Groix, in the Tauern Window, and on the island of Sifnos. The results should provide better constraints on the compositions of fluids present at high pressure and result in better models for devolatilization of subducting slabs.