成都理工大学学报（自然科学版）2025，Vol.52Issue(3)：480-501,22.DOI:10.12474/cdlgzrkx.2025021002
扬子西缘新元古代早期大洋俯冲作用——来自川西天全闪长岩成因的制约
Early Neoproterozoic oceanic subduction along the western Yangtze Block:Constraints from the genesis of Tianquan diorites in the western Sichuan
摘要
Abstract
Magmatic rocks exposed along the western margin of the Yangtze Block play a crucial role in reconstructing the Neoproterozoic tectonic evolution of the Yangtze Block.This study investigates diorite plutons in the Tianquan area of western Sichuan through U-Pb zircon dating,whole-rock major and trace element analysis,zircon Lu-Hf isotopic analysis,and whole-rock Sm-Nd isotope systematics.The Tianquan diorites formed 807～804 Ma,and are characterized by moderatew(SiO2)(55.71%～59.74%)and loww(K2O)(1.10%～1.77%),belonging to the calc-alkaline series.The diorites display arc-type features,including enrichment in light rare earth elements and large ion lithophile elements,depleted in high field strength elements,and significantly positive zircon εHf(t)(+10.0 to+12.9)and whole-rock εNd(t)(+4.25 to+4.43).Relatively high Ba/Th and low Th/La ratios suggest that the source was primarily metasomatized by subduction-related fluids.The whole-rock geochemical signatures and Nd-Hf isotopic compositions demonstrate that the Tianquan diorites originated from partial melting of a mantle wedge modified by subduction fluids,and the diorites were emplaced in an island arc environment.By integrating magmatic and sedimentary features along the western margin of the Yangtze Block,this study suggests that the western margin of the Yangtze Block was in a subduction tectonic setting in the early Neoproterozoic.关键词
天全闪长岩/地球化学/新元古代/岩石成因/扬子西缘Key words
Tianquan diorite/geochemistry/Neoproterozoic/petrogenesis/western Yangtze Block分类
天文与地球科学引用本文复制引用
李亚博,任祥,SAFONOVA Inna,裴秋明,甘保平,马啸阳,曹一鸣..扬子西缘新元古代早期大洋俯冲作用——来自川西天全闪长岩成因的制约[J].成都理工大学学报（自然科学版）,2025,52(3):480-501,22.基金项目
四川省重点研发计划项目(2022YFWZ0009) （2022YFWZ0009）
四川省博士后科研项目特别资助项目 （）
中央高校基本科研业务费项目(2682024CX080). （2682024CX080）
