地质通报2025，Vol.44Issue(9)：1681-1693,13.DOI:10.12097/gbc.2024.09.037
湘中紫云山花岗岩体中暗色包体的岩石成因:来自锆石U-Pb、Hf-O同位素的制约
Petrogenesis of the mafic microgranular enclaves in the Ziyunshan pluton,central Hunan Province:Constraints from zircon U-Pb and Hf-O isotopes
摘要
Abstract
[Objective]Previous studies of mafic microgranular enclaves(MMEs)and host granite have revealed that crust-mantle interaction plays an important role in the formation of granitic magma.However,whether MMEs and host granite are the products of different evolutionary stages of homologous magmas needs further exploration.[Methods]After petrography study,the MMEs from the Ziyunshan pluton were selected for zircon U-Pb and Hf-O isotopic compositions analyses to reveal their petrogenesis and genetic relationship with the host granite.[Results]U-Pb age of the MMEs is 225.1±5.3 Ma,which is in general agreement with the age(225.2±1.7 Ma to 227.0±2.2 Ma)of their host granites.The εHf(t)and δ18O values of the MMEs are-6.4 to-1.6 and 7.6‰to 9.9‰,respectively,and those are consistent with Hf-O isotope composition of their host granite.Two-stage model ages(TDM2)of the MMEs range from 1.35 Ga to 1.65 Ga(average at 1.51 Ga),which is slightly higher than that of the host granite(1.22 Ga to 1.79 Ga,average at 1.36 Ga).[Conclusions]The results indicate that the Ziyunshan MMEs and host granite are formed in post-collision tectonic setting.The initial magma chamber was firstly formed by the mantle magma and the anatectic magma in the lower crust.In the early stage,mixing of felsic magma and enriched mantle derived magma formed the host granite rich in MMEs.In the late stage,the more evolved and acidic residual magma emplaced into the host granite and mixed with a small amount of mantle-derived magma to form the complement granite and a small amount of MMEs.This study would provide a new perspective for understanding the genetic relationship between MMEs and their host granites.关键词
铁镁质暗色包体/岩石成因/锆石U-Pb年代学/Hf-O同位素/湘中Key words
mafic microgranular enclaves/petrogenesis/zircon U-Pb dating/Hf-O isotope/Central Hunan Province分类
天文与地球科学引用本文复制引用
鲁玉龙,涂恩搏,王鹏,彭建堂,黄建中,李欢,刘洋..湘中紫云山花岗岩体中暗色包体的岩石成因:来自锆石U-Pb、Hf-O同位素的制约[J].地质通报,2025,44(9):1681-1693,13.基金项目
湖南省自然科学基金项目《湘中三叠纪紫云山花岗岩中暗色微粒包体的岩石成因研究》(编号:2021JJ40197)、《湘东北稀贵金属矿集区深部电性结构建模及控矿机制研究》(编号:2023JJ60164)和矿床地球化学国家重点实验室开放基金项目《湘中三叠纪花岗岩及暗色微粒包体的成因研究——以紫云山、歇马岩体为例》(编号:202203) Supported by Natural Science Foundation of Hunan Province"Petrogenetic Study of Mafic Microgranular Enclave in Triassic Ziyunshan Granite in Central Hunan"(No.2021JJ40197)and"Deep Electrical Structure Modeling and Ore-Controlling Mechanisms of the Precious and Rare Metals Metallogenic Belt in Northeastern Hunan"(No.2023JJ60164),the Open Fund of the State Key Laboratory of Ore Deposit Geochemistry"Petrogenetic Study of Triassic Granite and Mafic Microgranular Enclave in Central Hunan:A Case Study of Ziyunshan and Xiema Plutons"(No.202203) （编号:2021JJ40197）
