成都理工大学学报（自然科学版）2025，Vol.52Issue(3)：394-408,15.DOI:10.12474/cdlgzrkx.2024112003
扬子克拉通北缘～630Ma裂解事件——来自A型花岗岩年代学和地球化学的制约
The～630 Ma rifting event in the northern margin of the Yangtze Craton:Constraints from geochronology and geochemistry of A-type granite
摘要
Abstract
The late Neoproterozoic tectonic evolution of the northern margin of the Yangtze Craton remains controversial,hindering our understanding of its position within the Rodinia supercontinent.Determining the formation age and nature of late Neoproterozoic magmatic rocks is crucial for constraining the tectonic setting of the northern margin of the Yangtze Craton.This paper reports for the first time the results of zircon U-Pb-Hf isotope,whole-rock geochemistry,and Sr-Nd isotope analyses conducted on newly discovered late Neoproterozoic syenogranite in the Dabie area.The zircon LA-ICP-MS chronology reveals that the formation age of the syenogranite is 630±4 Ma,belonging to a late Neoproterozoic magmatic event.The rocks have high contents of total alkali(K2O+Na2O,ranging from 7.49%to 8.27%,and FeOT/(FeOT+MgO),ranging from 0.97 to 0.99),as well as high Zr content(ranging from 289×10-6 to 431×10-6,with 104×Ga/Al values ranging from 2.98 to 5.02 and Zr+Nb+Ce+Y values ranging from 626×10-6 to 690×10-6).The zircon saturation temperature is as high as 847～891℃,indicating it is typical A-type granite.Its zircon εHf(t)values range from-0.5 to+1.3,corresponding to a TDM2 of 1 475～1 374 Ma,and the whole-rock εNd(t)values range from-4.5 to-4.4,corresponding to a TDM2 of 1 709～1 701 Ma;these indicate that the zircon was derived from partial melting of the Mesoproterozoic crust.Combined with the regional geological setting,the northern margin of the Yangtze Craton was in a continental rift environment during the late Neoproterozoic(～630 Ma).关键词
新元古代晚期/A型花岗岩/大陆裂谷/大别地区/扬子北缘Key words
late Neoproterozoic/A-type granite/continental rifting/Dabie area/northern margin of the Yangtze Craton分类
天文与地球科学引用本文复制引用
金巍,刘建辉,田洋,徐扬,邓新,刘述德..扬子克拉通北缘～630Ma裂解事件——来自A型花岗岩年代学和地球化学的制约[J].成都理工大学学报（自然科学版）,2025,52(3):394-408,15.基金项目
中国地质调查局项目(DD20240036,DD20221634) （DD20240036,DD20221634）
国家自然科学基金项目(42172218) （42172218）
湖北省自然科学基金项目(2024AFD375). （2024AFD375）
