江西德兴孔家—银山火山盆地的时代归属:锆石U-Pb年代学证据  

Age of Kongjia-Yinshan volcanic basin in Dexing,Jiangxi Province:evidence from zircon U-Pb chronology

作　　者：杨昔林[1,2] 曹殿华[3] 李以科[3] 黄玉凤[3] 阚迎松[3] 刘盛祥[1] 

机构地区：[1]中南大学地球科学与信息物理学院,湖南长沙410083 [2]江西铜业集团,江西贵溪335424 [3]中国地质科学院矿产资源研究所,北京100037

出　　处：《中国地质》2011年第1期86-93,共8页Geology in China

基　　金：国家科技支撑计划课题(2006BAB01B05)资助

摘　　要：江西银山铅锌多金属矿床是一个特大型火山-次火山热液矿床,容矿的孔家—银山火山盆地中火山-次火山岩通常被认为属于鹅湖岭组,但时代归属仍存在争议。本文对与银山火山岩伴生的英安斑岩进行了锆石LA-ICP-MS U-Pb年龄测定,获得了206Pb/238U年龄加权平均值为(181.3±2.1)Ma(MSWD=2.3,n=20),说明银山火山盆地形成于180 Ma左右,为早侏罗世的产物。对以往地质调查资料进行了分析,认为区域上鹅湖岭组为晚侏罗世有确切的地质证据,而早侏罗世孔家—银山火山盆地中火山-次火山岩不属于鹅湖岭组,该认识对研究区域地质演化及成矿规律有重要的意义。The Yinshan lead-zinc polymetallic deposit,a giant volcanics-associated hydrothermal ore deposit,is located in Dexing area,northeast Jiangxi Province.The volcanic and sub-volcanic rocks in the Kongjia-Yinshan basin,which constitute the host rocks of the ore deposit,are usually regarded as part of the Upper Jurassic Ehuling Formation,whose exact age,however,remains in question.The dacite porphyry associated with Yinshan volcanic rocks was dated by LA-ICP-MS U-Pb zircon geochronology.The precise geochronologic data indicate that the Kongjia-Yinshan volcanic basin was formed at（181.3±2.1）Ma.The fossil records and stratigraphic contact relationships suggest that the Ehuling Formation formed in late Jurassic.It is thus concluded that the early Jurassic volcanic and sub-volcanic rocks in the Kongjia-yinshan basin are not the component part of the Ehuling Formation.This result is of significance for the study of the regional geological evolution and the regional metallogenic system in this area.

关 键 词：银山 LA-ICP-MS U-PB 鹅湖岭组 

分 类 号：P597.3[天文地球—地球化学]