The composition of meta-gabbro and meta-basalt occurring abundant and widespread in all nappes of the nappe stack exposed in the Zermatt region of the Western Alp shows distinct patterns related to the geodynamic origin of metamorphic basic rocks. Eclogitic meta-basalts of the ophiolitic Zermatt-Saas Unit (ZSU) show enriched MORB signatures. The meta-basalts (eclogites) of the continental fragment of the Theodul Glacier Unit (TGU) derive from pre-Alpine metamorphic continental intraplate basalts. Meta-basalts (eclogites) from the continental basement of the Siviez-Mischabel nappe (SMN) derive from MORB thus a genetic relation to the TGU eclogites can be excluded. All basic igneous rocks experienced post-magmatic alteration by fluid-rock interaction ranging from processes at the seafloor, in the shallow crust, during subduction zone hydration, in the exhumation channel and late Alpine regional metamorphisms. The consequences of these alteration processes can be identified at various levels in the rock composition data. It was found that the REE data are little affected by fluid-rock alteration. Some trace elements, notably Cs, Rb, and Ba are typically massively altered relative to igneous compositions in all three groups of meta-basalts. Generally, meta-basalts from the TGU and the SMN preserved the features of the original composition whilst the ZSU meta-volcanic rocks experienced massive alteration. For the ZSU meta-volcanic rocks it is evident that Zr was gained and Y lost during high-pressure fluid-rock interaction indicating a mobile behavior of the two elements during HP-metamorphism in contrast to their behavior in hydrothermal near-surface fluid-rock interaction.

中文翻译：

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采尔马特地区（西阿尔卑斯山）的滑石质和大陆性尿布中的变质辉长岩和玄武岩

在西部阿尔卑斯山脉的采尔马特地区暴露的尿布叠层的所有尿布中，都富含和分布的玄武岩和玄武岩的成分显示出与变质基本岩石的地球动力学成因有关的独特模式。采尔马特-萨斯单元（ZSU）的火山岩偏玄武岩显示出丰富的MORB签名。Theodul冰川单元（TGU）大陆碎屑的超玄武岩（榴辉岩）源自阿尔卑斯山前变质大陆板内玄武岩。来自Siviez-Mischabel推覆（SMN）大陆基底的准玄武岩（榴辉岩）来源于MORB，因此可以排除与TGU榴辉岩的遗传关系。在俯冲带水化过程中，所有基础火成岩都经历了岩浆作用后的岩浆蚀变，其作用范围从海底，浅层地壳的过程到液化，出土通道中和晚期阿尔卑斯地区的变质作用。这些改变过程的结果可以在岩石成分数据的各个级别上得到识别。已经发现，REE数据几乎不受流体岩石蚀变的影响。在所有三组偏玄武岩中，一些痕量元素（尤其是Cs，Rb和Ba）相对于火成岩成分通常都会发生巨大变化。通常，来自TGU和SMN的玄武岩保留了原始成分的特征，而ZSU的超火山岩经历了巨大的蚀变。对于ZSU中火山岩，很明显在高压流体-岩石相互作用中Zr的获得和Y的损失，表明这两个元素在HP变质过程中的移动行为与其在热液近地表流体岩石中的行为相反。相互作用。