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3.85 Ga continental crust beneath the southern North China Craton: Evidence from zircon xenocrysts in cretaceous granites
Gondwana Research ( IF 7.2 ) Pub Date : 2021-03-01 , DOI: 10.1016/j.gr.2020.11.013
Nan Qi , Zhenju Zhou , Haibo Zou , Yanjing Chen

Abstract A fragment of Hadean continental crust has been postulated to underlie the North China Craton based on the discovery of >3.8 Ga detrital zircons, but these detrital zircons may be transported from a lateral source. Here we report new U Pb ages of 3823 to 230 Ma for zircon xenocrysts directly from Cretaceous granites (129 Ma), which rules out a lateral source. Our results for the first time demonstrate the existence of 3.85 Ga crustal precursors beneath the southern North China Craton based on the Hf isotopic compositions of the 3.82 Ga zircon. The crustal precursors might be a granitic source that was produced by the wet melting of ancient continental crust. We further show that the southern North China Craton has experienced the global Columbia, Gondwana, and Pangaea supercontinent events, based on the inherited zircon age groups of 2017–1896 Ma, 1792–1776 Ma, 584–570 Ma and 251–230 Ma. These Eoarchaean to Triassic U Pb ages document the evolution of the early continental crust and the geological process in the development of the North China Craton.

中文翻译:

华北克拉通南部3.85 Ga陆壳:来自白垩纪花岗岩中锆石异晶的证据

摘要 基于>3.8 Ga 碎屑锆石的发现,推测冥河大陆地壳碎片位于华北克拉通的下方,但这些碎屑锆石可能来自侧向源。在这里,我们报告了直接来自白垩纪花岗岩(129 Ma)的锆石异种晶体的新 U Pb 年龄为 3823 至 230 Ma,这排除了侧向来源。我们的研究结果首次基于 3.82 Ga 锆石的 Hf 同位素组成证明了华北克拉通南部下方存在 3.85 Ga 地壳前体。地壳前体可能是古大陆地壳湿熔产生的花岗岩源。我们进一步表明华北克拉通南部经历了全球哥伦比亚、冈瓦纳和盘古超大陆事件,基于 2017-1896 Ma、1792-1776 Ma、584-570 Ma 和 251-230 Ma 的继承锆石年龄组。这些始太古至三叠纪 U Pb 年龄记录了早期大陆地壳的演化和华北克拉通发育的地质过程。
更新日期:2021-03-01
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