The Archean-Proterozoic transition heralded a number of fundamental changes on Earth, including the oxygenation of the atmosphere, a marked emergence of continents above sea-level, and an increase in δ¹⁸O of felsic magmas. The potential drivers for the latter are changes in the composition of supracrustal material or increased crustal reworking. Although the onset of subduction-induced continental collision and associated enhanced crustal recycling could produce high-δ¹⁸O felsic magmas, temporally constrained zircon δ¹⁸O reveals an increase in δ¹⁸O at ~2.35 Ga that predates the oldest widely recognized supercontinent. In this work, we use the O and Hf isotope ratios of magmatic zircon crystals in Archean and Proterozoic sediment-derived granitoids of the North China Craton to track the incorporation of supracrustal material into magmas. The results are consistent with a Paleoproterozoic increase of continental freeboard producing sedimentary reservoirs with comparatively elevated δ¹⁸O that subsequently partially melted to generate the granitoids.

中文翻译：

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海平面以上大陆的出现影响沉积物熔体成分

太古代-元古代过渡预示着地球上的许多根本性变化，包括大气的氧化、海平面以上大陆的显着出现以及长英质岩浆的δ ¹⁸ O增加。后者的潜在驱动因素是地壳上物质成分的变化或地壳改造增加。尽管俯冲引起的大陆碰撞的开始和相关的地壳循环增强可能产生高δ ¹⁸ O 长英质岩浆，但时间受限的锆石δ ¹⁸ O 显示δ ¹⁸增加O 在~2.35 Ga，早于最古老的被广泛认可的超大陆。在这项工作中，我们利用华北克拉通太古宙和元古代沉积物衍生的花岗岩中岩浆锆石晶体的 O 和 Hf 同位素比值来追踪地壳上物质与岩浆的结合。结果与古元古代大陆干舷生产沉积储层相一致，δ ¹⁸ O相对升高，随后部分熔化生成花岗岩。