江南造山带南段淘金冲矿集区辉绿岩LA-ICP-MS锆石U-Pb定年及地质意义  

LA-ICP-MS Zircon U-Pb Dating and Geological Significance of Diabase Located Taojinchong Ore Concentration Area In South Section of Jiangnan Orogenic Belt

作　　者：李永德 吕书君 彭思才 董裕军 Li Yongde;Lyu Shujun;Peng Sicai;Dong Yujun(Natural Resources Investigation Institute of Hunan Province,Changsha Hunan 410004)

机构地区：[1]湖南省自然资源调查所,湖南长沙410004

出　　处：《国土资源导刊》2025年第1期80-88,共9页Land & Resources Herald

基　　金：湖南省地质院科技计划项目资助(编号:HNGSTP202465)。

摘　　要：文章的研究对象为江南造山带南段雪峰山地区淘金冲矿集区辉绿岩,该矿集区已发现淘金冲、大叶塘、漠滨、爱山冲等多个大中型金矿床,均赋存于板溪群凝灰质板岩中。以往同位素与稀土元素分析揭示成矿物质与岩浆活动具地球化学亲缘性,为进一步解析辉绿岩与金矿成因联系,通过野外地质调查、岩相学与矿相学观测,采用LA-ICP-MS锆石U-Pb定年获得辉绿岩侵位年龄(798.8±2.7)Ma,确认为新元古代基性岩浆事件。淘金冲矿集区辉绿岩与雪峰山地区的铲子坪金矿区细碧岩、字溪金矿区辉绿岩、隘口地区基性岩墙年龄一致,这些基性岩具有明显的洋岛玄武岩(OIB)地球化学特征,其形成环境为板内裂谷。结合年代学结果及以往地球化学数据,认为淘金冲矿集区辉绿岩可能为新元古代扬子板块与华夏板块碰撞造山后Rodinia大陆裂解过程中形成的产物,极有可能与江南造山带南段金成矿作用相关,造成地层中成矿物质的初始富集。The research object of this article is the diabase in the Taojinchong ore concentration area of the Xuefengshan region in the southern segment of the Jiangnan orogenic belt.Multiple large and medium-sized gold deposits,such as Taojinchong,Dayetang,Mobin,and Aishanchong,have been discovered in this ore concentration area,all hosted in the tuffaceous slate of the Banxi group.Previous isotopic and rare earth element(REE)analyses revealed a geochemical affinity between ore-forming materials and magmatic activities.To further elucidate the genetic linkage between diabase and gold mineralization,integrated field investigations,petrographic and mineragraphic observations,combined with LA-ICP-MS zircon U-Pb dating,were conducted,yielding a diabase emplacement age of(798.8±2.7)Ma.This age confirms a Neoproterozoic mafic magmatic event.The diabase in the Taojinchong ore concentration area is consistent in age with the spilite in the Chanziping gold mining area,the diabase in the Zixi gold mining area,and the basic dykes in the Aikou area of Xuefengshan area.These basic rocks exhibit distinct OIB geochemical characteristics,indicating that their formation environment is an intraplate rift.Combining the chronological results with previous geochemical data,it is believed that the diabase in the Taojinchong ore concentration area may have been formed during the Rodinia continental breakup process following the collision orogeny between the Yangtze plate and the Cathaysian late in the Neoproterozoic era.It is highly likely that it is related to the gold mineralization in the southern segment of the Jiangnan orogenic belt,causing initial enrichment of ore-forming materials in the strata.

关 键 词：淘金冲矿集区 基性侵入岩 锆石U-Pb定年 江南造山带南段 

分 类 号：P618.6[天文地球—矿床学]