岩石矿物学杂志2025，Vol.44Issue(5)：1051-1070,20.DOI:10.20086/j.cnki.yskw.2025.4157
扬子西缘中元古代晚期双峰式岩浆岩年代学及其构造意义
Chronology of late Mesoproterozoic bimodal igneous rocks in the western margin of the Yangtze Block and its tectonic significance
摘要
Abstract
The late Mesoproterozoic igneous rocks in the western margin of Yangtze Block are important for under-standing the tectonic evolution and its role in reconstruction of the Rodinia supercontinent.In this paper,we report new zircon U-Pb ages,whole rock major and trace elements,and Nd-Hf isotopic analyses of the plagioclase am-phibolites and granites in the Cuoke area on the western margin of the Yangtze Block.Geochronological results show that the granites and plagioclase amphibolites have similar late Mesoproterozoic zircon U-Pb ages of 1 160.5 Ma and 1 170.2 Ma,constituting a bimodal igneous assemblage.The plagioclase amphibolites belong to the tholeiite se-ries and characterized by enrichment in LREEs and LILEs,and have OIB-like affinities with No obvious Nb and Ta anomalies,and with positive εNd(t)and εHf(t)values,indicating that they were derived from the asthenospheric mantle source.The granites belong to the peralkaline A-type series and characterized by have high Fe/Mg and Ga/Al ratios,with positive εNd(t)value and εHf(t)values,indicating that they were derived partially from the newly formed crust.Geochemical characteristics indicate that the Cuoke plagioclase amphibolite and granite were likely formed in an intra-plate rift basin on the passive continental margin,and are unrelated to the Grenvillian Orogen in the western Yangtze Block.Based on previous research results,it is believed that the western margin of the Yangtze Block during the late Mesoproterozoic belonged to a passive continental margin rift environment,and the Yangtze Block was in the peripheral rather in the center in the configuration of Rodinia.关键词
中元古代晚期/双峰式岩浆岩/地球化学/大陆裂谷/扬子陆块Key words
late Mesoproterozoic/bimodal igneous rock/geochemistry/continental rift/Yangtze Block分类
天文与地球科学引用本文复制引用
吴迪,康璐燕,安楚..扬子西缘中元古代晚期双峰式岩浆岩年代学及其构造意义[J].岩石矿物学杂志,2025,44(5):1051-1070,20.基金项目
陕西地调融媒体平台建设与服务研究项目(202006) Research on the Construction and Service of Shaanxi Geological Survey's Integrated Media Platform(202006) （202006）
