赣南兴国留龙金矿田井头复式岩体锆石SHRIMP U-Pb定年及地质意义  

SHRIMP U-Pb dating of Jingtou composite pluton in Liulong gold orefield of Xingguo County, southern Jiangxi Province, and its geological significance

作　　者：刘善宝[1] 王登红[2] 陈毓川[1] 张建[1] 许建祥[3] 曾载淋[4] 应立娟[1] 王成辉[1] 范世祥[4] 张永忠[4] 赖志坚[4] 

机构地区：[1]中国地质科学院,北京100037 [2]中国地质科学院矿产资源研究所,北京100037 [3]江西省国土资源厅,江西南昌330000 [4]江西省赣南地质调查大队,江西赣州341000

出　　处：《矿床地质》2010年第2期290-300,共11页Mineral Deposits

基　　金：国家科技支撑计划"南岭地区有色-贵重金属成矿潜力及综合探测技术示范研究"课题;中国地质科学院矿产资源研究所基本业务费专项资金(项目编号K0906)"我国重要矿产和区域成矿规律研究"项目的联合资助

摘　　要：赣南兴国县留龙金矿田井头复式岩体由主体花岗闪长岩和补体闪长岩组成,其中闪长岩主要由角闪石和斜长石组成,而不是英安岩或粗玄岩,其主体和补体的稀土元素球粒陨石标准化配分曲线相互平行,属于轻稀土元素富集型,Eu有弱的亏损,两者来源于同一个岩浆房;并发现了具有金矿化特征的绿泥石化蚀变闪长岩,是一个新的地质找矿方向;锆石SHRIMP U-Pb同位素年代学研究表明,井头复式岩体的主体花岗闪长岩的成岩年龄为(162.6±2.6)Ma(MSWD=0.75),具有金矿化特征的绿泥石化蚀变闪长岩的成岩年龄为(156.6±1.7)Ma(MSWD=0.46)。区域地质及井头复式岩体的地球化学分析显示,该区金矿的形成与中晚侏罗世的浅成相中酸性、中性或基性岩浆岩密切相关,与赣南地区燕山早期钨锡矿的成矿时代同步,在同一构造背景下形成,两者应属于同一成矿系列。The Jingtou composite pluton in the Liulong gold orefield of southern Jiangxi Province is composed of the main body of granitic diotite and the patched body of diorite. Certain extent of gold mineralization was found in the chloritized patched body, implying a new prospecting direction in southern Jiangxi. In this paper,SHRIMP U-Pb technique was employed to date the ages of the main body and the altered patched body. The dating result of the main body is （162.6±2.6）Ma （MSWD=0.75）, whereas the age of the chloritized patched body is （156.6±1.7）Ma（MSWD=0.46）. These data imply that the main body and the patched body might have resulted from the same magma reservoir. From regional geological information and researches on geochemical characteristics of Jingtou composite pluton, some conclusions have been reached： （1） the intrusion of Jingtou composite pluton took place in Middle Jurassic, and the minor body characterized by further differentiation should be the extensional product of the lithosphere; （2） during the intrusion of the middle-plutonic granite to the hypabyssal diortite-trachydolerite, the magmatic activities lasted for 6 Ma, suggesting that there existed a concentrated period of Au and W/Sn mineralization; （3） in southern Jiangxi Province, the metallogenic age of Au are basically concordant with that of W/Sn, and the ore-forming processes are mainly concentrated in the period of 150～165 Ma.

关 键 词：地球化学 SHRIMP 井头复式岩体 金矿 钨锡矿 赣南 

分 类 号：P618.67[天文地球—矿床学]