Kimberlite-borne xenolithic eclogites, typically occurring in or near cratons, have long been recognized as remnants of Precambrian subducted oceanic crust that have undergone partial melting to yield granitoids similar to the Archean continental crust. While some eclogitized oceanic crust was emplaced into cratonic lithospheres, the majority was deeply subducted to form lithologic and geochemical heterogeneities in the convecting mantle. If we accept that most xenolithic eclogites originally formed at Earth's surface, then their geodynamic significance encompasses four tectonic environments: (a) spreading ridges, where precursors formed by partial melting of convecting mantle and subsequent melt differentiation; (b) subduction zones, where oceanic crust was metamorphosed and interacted with other slab lithologies; (c) the cratonic mantle lithosphere, where the eclogite source was variably modified subsequent to emplacement in Mesoarchean to Paleoproterozoic time; and (d) the convecting mantle, into which the vast majority of subduction-modified oceanic crust not captured in the cratonic lithosphere was recycled. ▪Xenolithic eclogites are fragments of ca. 3.0–1.8 Ga oceanic crust and signal robust subduction tectonics from the Mesoarchean.▪Multiple constraints indicate an origin as variably differentiated oceanic crust, followed by subduction metamorphism, and prolonged mantle residence. ▪Xenolithic eclogites thus permit investigation of deep geochemical cycles related to recycling of Precambrian oceanic crust.▪They help constrain asthenosphere thermal plus redox evolution and contribute to cratonic physical properties and mineral endowments.

中文翻译：

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异石质岩的岩石成因和地球动力学意义


金伯利岩携带的异石器榴辉岩，通常出现在克拉通内或附近，长期以来一直被认为是前寒武纪俯冲海洋地壳的残余物，这些地壳经历了部分熔化，产生了类似于太古宙大陆地壳的花岗岩。虽然一些生态化海洋地壳被置于克拉通岩石圈中，但大部分被深深俯冲，在对流地幔中形成岩性和地球化学非均质性。如果我们接受大多数异石器时代榴辉岩最初形成于地球表面，那么它们的地球动力学意义包括四种构造环境：（a） 扩张的山脊，其中前体由对流地幔的部分熔化和随后的熔融分化形成;（b） 俯冲带，海洋地壳变质并与其他板岩性相互作用;（c） 克拉通地幔岩石圈，其中榴辉岩源在中太古代至古元古代放置后发生了不同的变化;（d） 对流地幔，绝大多数未在克拉通岩石圈中捕获的俯冲改性海洋地壳被回收到该地幔中。▪异石器纪榴辉岩是约 3.0-1.8 Ga 海洋地壳的碎片，标志着来自中太古代的强大俯冲构造。 ▪▪因此，异石质榴辉岩允许研究与前寒武纪海洋地壳循环相关的深部地球化学循环，▪它们有助于限制软流圈热加氧化还原演化，并有助于克拉通物理性质和矿物禀赋。