Zircon oxygen isotope ratios have been used to trace the incorporation of sedimentary rocks into magmas. The dramatic increase in maximum zircon δ¹⁸O values in the Paleoproterozoic observed in global databases coincides with changes in surface environments (e.g., the rise of subaerial and oxidative weathering), implying a connection between elevated zircon δ¹⁸O and these changes. Zircon δ¹⁸O between 2.5 to 2.2 Ga, however, is relatively under-constrained owing to limited available data in this age range. To augment data from this critical time period and understand potential causes for the elevated zircon δ¹⁸O values, we report U-Pb zircon ages and δ¹⁸O values of zircon, as well as, whole-rock major and trace element geochemistry of Paleoproterozoic strongly peraluminous granites (SPGs) from the southwestern margin of the Yangtze Block (China). Our geochronological data demonstrate that these SPGs crystallized at ∼2.35 Ga and that inherited zircon with ages of 2428-2721 Ma are present in these granites, indicating the source rocks of these granites were deposited, subsequently metamorphosed, and partially melted between 2.43 to 2.35 Ga. Synmagmatic zircon from samples dated in this study have ε_Hf(t) values of −6.4 to −0.9 and high δ¹⁸O values of 7.6 to 9.9‰, elevated above the maximum value observed in Archean zircon (∼7‰). These granites can be divided into two groups based on whole-rock geochemistry. Both Group 1 and Group 2 granites were derived from a similar high δ¹⁸O, metapelitic source, but were generated by dehydration melting and hydrous melting, respectively. Our results demonstrate that the fine-grained sedimentary rocks from which the SPGs were derived had relatively high δ¹⁸O (as compared to older sedimentary rocks) by 2.43-2.35 Ga. The depositional time interval of the high-δ¹⁸O sedimentary sources for SPGs studied here coincides with the emergence of continental crust above sea level and the Great Oxidation Event. Supporting the findings of previous studies, the contemporaneity of our dataset with these changes in Earth’s surface environments suggests that subaerial and potentially oxidative weathering contributed (at least partially) to the elevation of δ¹⁸O of fine-grained sedimentary rocks. Recycling of these high-δ¹⁸O sedimentary rocks into magmas contributed to the dramatic change in δ¹⁸O of magmatic zircon in the earliest Paleoproterozoic. In addition, although this study is focused on a single locality, our results suggest that the abrupt shift observed in global zircon δ¹⁸O data sets likely occurred by 2.35 Ga. Last, a literature compilation of zircon δ¹⁸O data from SPGs suggested that zircon δ¹⁸O values may have also experienced a stepwise increase in the Neoproterozoic to Phanerozoic from 12 to 14‰. The coincidence of these increases in zircon δ¹⁸O values with global oxygenation events suggests that atmospheric oxygenation may have contributed to the increase in δ¹⁸O of sedimentary rocks.

锆石氧同位素比率已被用于追踪沉积岩与岩浆的结合。^{在全球数据库中观察到的古元古代最大锆石δ 18} O 值的急剧增加与地表环境的变化（例如，陆上和氧化风化的上升）相吻合，这意味着锆石δ ¹⁸ O 升高与这些变化之间存在联系。然而，在 2.5 到 2.2 Ga 之间的锆石 δ ^{18 O 由于在这个年龄范围内的可用数据有限而受到相对不足的约束。}为了增加这一关键时期的数据并了解锆石 δ ¹⁸ O 值升高的潜在原因，我们报告了 U-Pb 锆石年龄和 δ ¹⁸扬子地块西南缘古元古代强过铝花岗岩（SPGs）锆石O值及全岩主、微量元素地球化学[J]. 我们的地质年代学数据表明，这些 SPG 结晶的时间约为 2.35 Ga，并且这些花岗岩中存在年龄为 2428-2721 Ma 的继承锆石，表明这些花岗岩的烃源岩在 2.43 至 2.35 Ga 之间沉积、随后变质和部分熔融. 来自本研究年代样品的同岩浆锆石的 ε _Hf (t) 值为 -6.4 至 -0.9 和高 δ ¹⁸O 值为 7.6 至 9.9‰，高于在太古宙锆石中观察到的最大值（~7‰）。根据全岩地球化学，这些花岗岩可分为两类。第 1 组和第 2 组花岗岩均来自类似的高 δ ¹⁸ O 变泥质岩源，但分别由脱水熔融和含水熔融产生。我们的研究结果表明，产生 SPG 的细粒沉积岩具有相对较高的 δ ¹⁸ O（与较老的沉积岩相比）高 2.43-2.35 Ga。高 δ ^{18的沉积时间间隔}这里研究的 SPGs 的 O 沉积源与海平面以上大陆地壳的出现和大氧化事件相吻合。支持先前研究的结果，我们的数据集与地球表面环境的这些变化的同时性表明，地面和潜在的氧化风化（至少部分地）促成了细粒沉积岩δ ^{18 O 的升高。}这些高δ ¹⁸ O沉积岩再循环成岩浆，促成了最早古元古代岩浆锆石δ ^{18 O的剧烈变化。}此外，虽然这项研究集中在一个单一的地点，但我们的结果表明，在全球锆石 δ ^{18中观察到的突然变化}O 数据集可能出现在 2.35 Ga。最后，来自 SPG的锆石 δ ^{18 O 数据的文献汇编表明，新元古代到显生宙的锆石 δ 18} O 值也可能从 12‰逐步增加到 14‰。^{锆石 δ 18} O 值的这些增加与全球氧化事件的一致性表明，大气氧化可能促成了沉积岩δ ^{18 O 的增加。}