Abstract Modern style plate tectonics is characterized by one-sided subduction and continental margin basalt-andesite-dacite-rhyolite (BADR) magmatism, whereas continental magmatic rocks in the Archaean record had tonalite-trondjhemite-granodiorite (TTG) composition. Their main difference is the absence (in the modern style) and the presence (in the ancient style) of abundant juvenile, basalt-derived felsic magmatism. The diversity of modern continental magmas depends partly on metasomatic processes in the mantle wedge providing sediment input (melt/fluid). Contrasting scenarios in the rock record therefore are the presence or absence of (1) basalt-derived melt (TTG) and (2) sedimentary input to the magmas. A late, “Archaean-style” tectonic regime is recorded in the Palaeoproterozoic Mineiro Belt (Brazil) using whole-rock geochemistry of its plutons coupled to zircon Hf and O isotopes from these rocks and from detrital grains from the local (meta)sediments. Increasing δ 18 O with decreasing eHf(t) values in zircon indicate oceanic crust recycling and input of sediments to the mantle wedge during the Palaeoproterozoic. Since some form of early subduction including the formation of a mantle wedge has occurred since the Mesoarchaean, it seems that the onset of subduction and the final establishment of modern plate tectonics at the global scale are temporally distinct. The latter did not occur until the Palaeoproterozoic. Prior to this time (“ante-plate tectonics”), punctuated subcretion/subduction marks a gestational stage that took c. 800 Myr to transition diachronously to a truly global mechanism. The TTG-sanukitoid transition, which signals the opening of a mantle wedge, occurred in the Mineiro Belt during the early Proterozoic “magmatic lull” and thus represents the last gasp of the ante-plate tectonics regime.

中文翻译：

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板块构造临界点的岩石成因过程：地球最后一次 TTG 到 sanukitoid 过渡的 Hf-O 同位素三元模型

摘要 现代风格板块构造以单向俯冲和大陆边缘玄武岩-安山岩-英安岩-流纹岩（BADR）岩浆作用为特征，而太古宙记录中的大陆岩浆岩具有辉长岩-长闪长岩-花岗闪长岩（TTG）组成。它们的主要区别是缺乏（现代风格）和存在（古代风格）丰富的幼年玄武岩长英质岩浆。现代大陆岩浆的多样性部分取决于提供沉积物输入（熔体/流体）的地幔楔中的交代过程。因此，岩石记录中的对比情景是 (1) 玄武岩熔体 (TTG) 和 (2) 沉积输入岩浆的存在与否。迟到，“太古代风格”构造体制记录在古元古代米内罗带（巴西）中，利用其岩体的全岩地球化学与这些岩石中的锆石 Hf 和 O 同位素以及来自当地（变质）沉积物的碎屑颗粒耦合。随着锆石中 eHf(t) 值的降低，δ 18 O 增加表明古元古代期间洋壳循环和沉积物输入地幔楔。由于自中古宙以来发生了某种形式的早期俯冲，包括地幔楔的形成，似乎俯冲的开始和全球范围内现代板块构造的最终建立在时间上是不同的。后者直到古元古代才发生。在此之前（“前板块构造”），间断性下沉/俯冲标志着一个妊娠阶段，该阶段花费了 c。800 Myr 以历时过渡到真正的全球机制。TTG-sanukitoid 转变标志着地幔楔的打开，发生在早元古代“岩浆停滞”期间的米内罗带，因此代表了前板块构造体系的最后一次喘息。