Abstract South China is characterized by widespread igneous rocks with varied ages and nature in its eastern part, which contain abundant Precambrian xenocrystic/inherited zircons that bear important information of the composition and evolution of the underlying ancient crust. This paper for the first time presents a compiled U-Pb age database of 1416 Precambrian xenocrystic/inherited zircons from igneous rocks in eastern South China, and attempts to provide a constraint on the Precambrian crustal evolution of the constituent Yangtze and Cathaysia blocks. These xenocrystic/inherited zircons, as a conceivable proxy of the unexposed continental crust, document three major tectonothermal events related to continental accretion and subsequent modification that possibly built the continental crust of the eastern Yangtze Block (EYB) at 2.70–2.40 Ga, 2.10–1.55 Ga, and 0.95–0.70 Ga, and the Cathaysia Block (CAB) at 2.70–2.40 Ga, 2.05–1.75 Ga, and 1.10–0.70 Ga, pointing to a complex Precambrian evolutionary history for South China. The EYB zircons are unexpectedly dominated by a 2.10–1.55 Ga age population that shows a multimodal distribution with peaks at 2.05 Ga, 2.0 Ga, 1.90 Ga, 1.85 Ga, and 1.58 Ga, and the CAB zircons are characterized by a unimodal 2.0–1.75 Ga age population that conspicuously peaked at 1.85 Ga, both of which overlap with the tenure of the Nuna supercontinent. These xenocrystic/inherited zircons from both blocks generally have negative eHf(t) values, which in combination with coeval regional magmatic and metamorphic records can assist to trace a possible prolonged (2.05–1.75 Ga) orogenic process in the EYB and a short-lived (1.9–1.8 Ga) orogeny in the CAB. Such orogeneses are proposed to be correlated with the assembly of the Nuna supercontinent.

中文翻译：

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华南东部火成岩中夹带的异晶/继承前寒武纪锆石：追踪未暴露的古地壳及其对晚古元古代造山作用的影响

摘要 华南东部地区分布着不同年代和性质的火成岩，其中含有丰富的前寒武纪异晶/继承锆石，是下伏古地壳组成和演化的重要信息。本文首次提出了华南东部火成岩中1416颗前寒武纪异晶/继承锆石的U-Pb年龄数据库，并试图为构成扬子和华夏地块的前寒武纪地壳演化提供约束。这些异晶/继承的锆石作为未暴露的大陆地壳的一个可能代表，记录了与大陆增生和随后的修改有关的三个主要构造热事件，这些事件可能在 2.70-2.40 Ga，2. 2. 建立了东部扬子地块 (EYB) 的大陆地壳。10-1.55 Ga 和 0.95-0.70 Ga，以及 2.70-2.40 Ga、2.05-1.75 Ga 和 1.10-0.70 Ga 的华夏地块 (CAB)，表明华南具有复杂的前寒武纪演化历史。EYB 锆石出人意料地以 2.10-1.55 Ga 年龄群为主，显示出多峰分布，峰值在 2.05 Ga、2.0 Ga、1.90 Ga、1.85 Ga 和 1.58 Ga，而 CAB 锆石的特征是单峰 2.0-1。 Ga 年龄人口显着达到 1.85 Ga 的峰值，这两者都与 Nuna 超大陆的任期重叠。这些来自两个区块的异晶/继承锆石通常具有负的 eHf(t) 值，结合同时期的区域岩浆和变质记录可以帮助追踪 EYB 中可能的长期 (2.05-1.75 Ga) 造山过程和短暂的造山过程(1.9–1.8 Ga) CAB 中的造山运动。