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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捕虏榴辉岩的岩石成因及地球动力学意义


金伯利岩中的捕虏榴辉岩通常出现在克拉通内或克拉通附近，长期以来一直被认为是前寒武纪俯冲洋壳的残余物，这些洋壳经历了部分熔融，产生了类似于太古代大陆地壳的花岗岩。虽然一些榴辉岩化的洋壳进入了克拉通岩石圈，但大多数都被深深俯冲，在对流地幔中形成岩性和地球化学异质性。如果我们承认大多数捕虏榴辉岩最初形成于地球表面，那么它们的地球动力学意义涵盖四种构造环境：（a）扩张山脊，其中前体是由对流地幔部分熔融和随后的熔融分异形成的； (b) 俯冲带，洋壳在此发生变质并与其他板块岩性相互作用； (c) 克拉通地幔岩石圈，其中榴辉岩来源在中太古代到古元古代时期的侵位后发生了不同程度的改变； (d)对流地幔，克拉通岩石圈中未被捕获的绝大多数俯冲改变的洋壳被回收到其中。 ▪ 捕猎榴辉岩是大约的碎片。 3.0–1.8 Ga 洋壳和来自中太古代的强烈俯冲构造信号。 ▪ 多重约束表明起源是不同分化的洋壳，随后是俯冲变质作用和长期地幔居住。 ▪ 因此，包石榴辉岩可以研究与前寒武纪洋壳循环相关的深层地球化学循环。 ▪ 它们有助于限制软流圈热演化和氧化还原演化，并有助于克拉通物理性质和矿物禀赋。