We document the complex interaction between metamorphic reactions and deformation behaviour at high-pressure conditions by combining (micro-) structural, petrographical and geochemical data from an eclogite body. The well-equilibrated eclogite fabric is crosscut by mineral veins. Precipitated veins host the eclogitic high-pressure assemblage with variation in modal composition, indicating that fracturing occurred at eclogite facies conditions. Deflection of the eclogite fabric adjacent to the veins implies ductile reactivation of the veins as flanking structures and strain localization under continuous aseismic shearing. In consequence, the reactivated veins are characterized by undulatory extinction and subgrain formation in quartz indicating crystal plasticity. We show that prograde post-eclogitization metamorphism resulted in progressive dehydration and melting of the eclogite. Subsequent increase in pore-pressure-induced rock failure. The mesoscopic to microscopic characteristics of eclogite-facies veins indicate a cyclic behaviour of fracturing, vein formation and crystal-plasticity which demonstrates the strong interaction of chemical and mechanical processes operating at depth.

中文翻译：

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高压条件下榴辉岩脱水和熔体脆化

我们通过结合榴辉岩体的（微观）结构、岩石学和地球化学数据，记录了高压条件下变质反应和变形行为之间的复杂相互作用。均衡良好的榴辉岩组构被矿脉横切。沉积岩脉中存在着榴辉岩高压组合，其模态成分存在变化，表明在榴辉岩相条件下发生了破裂。邻近矿脉的榴辉岩组构的偏转意味着矿脉作为侧翼结构的延性重新激活和连续抗震剪切下的应变局部化。因此，重新激活的矿脉的特征是石英中的波状消光和亚晶粒形成，表明晶体可塑性。我们表明，榴辉岩化后进行的变质作用导致了榴辉岩的逐渐脱水和熔化。随后孔隙压力引起的岩石破坏增加。榴辉岩相脉的细观到微观特征表明了断裂、脉形成和晶体塑性的循环行为，这表明了在深处发生的化学和机械过程的强烈相互作用。