The compositional similarity between high-Mg andesite-dacite from accretionary orogens and bulk continental crust (CC) provides an opportunity to unravel the CC formation paradox. Compositional data from a global compilation of Quaternary magmatic arcs indicate the presence of low-Mg series (LMS) and high-Mg series (HMS). The LMS show trends of crystal fractionation and can be subdivided into high Ba/Th and high La/Sm groups, which likely originate from fluid- and sediment melt-modified mantle wedge, respectively. In contrast, the HMS have variably mixed compositions (e.g., high Mg#, Ba/Th, and La/Sm) and can be explained by partial melting of mélange diapirs rising into the mantle wedge, which are mixtures of subducted sediment, eroded arc crust or CC, buoyant oceanic crust, and peridotite. We, therefore, propose a two-step process for creating CC involving extraction of LMS from the mantle followed by re-melting of recycled LMS in the mantle to generate HMS and thus CC.

中文翻译：

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地幔楔中循环地壳物质的底辟熔融形成大陆地壳

增生造山带的高镁安山岩-英安岩与大块大陆地壳 (CC) 之间的成分相似性为解开 CC 形成悖论提供了机会。来自全球第四纪岩浆弧汇编的成分数据表明存在低镁系列（LMS）和高镁系列（HMS）。LMS 显示晶体分馏趋势，可细分为高 Ba/Th 和高 La/Sm 组，它们可能分别来自流体和沉积物熔融改性的地幔楔。相比之下，HMS 具有不同的混合成分（例如，高 Mg#、Ba/Th 和 La/Sm），并且可以通过上升到地幔楔的混杂底辟部分熔融来解释，这些混杂底辟是俯冲沉积物、侵蚀弧的混合物地壳或CC，浮力大洋地壳和橄榄岩。因此，我们，