福建漳平北坑场钼多金属矿床辉钼矿Re-Os同位素年龄及其地质意义  

Re-Os Isotopic Age of Molybdenite from the Beikengchang Molybdenite and Polymetal Deposit in Zhangping City,Fujian Province and Its Geological Significance

作　　者：张达[1,2] 吴淦国[1,2] 刘乃忠[3,4] 狄永军[1] 吕良冀[1] 曹文融[5] 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,北京100083 [2]中国地质大学岩石圈构造、深部过程及探测技术教育部重点实验室,北京100083 [3]中国地质大学(武汉)资源学院,武汉430074 [4]福建省地质调查研究院,福州350003 [5]南加州大学地球科学系,洛杉矶90089

出　　处：《地质学报》2010年第10期1428-1437,共10页Acta Geologica Sinica

基　　金：中国地质调查项目“武夷山成矿带铜多金属成矿规律研究”(编号1212010533105);“武夷山成矿带中生代推覆构造与铜多金属找矿方向研究”(编号1212010813064);“武夷山植被覆盖区成矿地质背景研究与成矿要素综合推断”(编号1212010070203);“111”计划(编号B07011)资助成果

摘　　要：福建漳平钼多金属矿床位于闽西南晚古生代坳陷东缘。中生代以来,闽西南坳陷经历了强烈的构造岩浆作用的改造,并伴随多期次成矿作用的发生。已有同位素年代学研究成果表明该区存在早侏罗世、中侏罗世以及早白垩世成矿作用,但缺少与晚侏罗世大规模岩浆作用相关的成矿年代学记录。本文选取漳平北坑场钼多金属矿床开展辉钼矿的Re-Os同位素年代学研究。根据Re-Os同位素测年结果,结合矿床围岩蚀变及矿化特征以及与岩体的相互关系,指出钼矿化的形成经历了多个成矿阶段,其中小规模的矿化发生在148.8±2.2Ma。主矿化阶段形成的矿床以细脉或网脉状赋存于下二叠统翠屏山组石英细砂岩中,其等时线年龄为139.8±2.3～143.7±2.1Ma,为晚侏罗世—早白垩世成矿。成矿物质主要来源于特提斯向环太平洋构造域转换后闽西南地区晚侏罗世—早白垩世壳源花岗岩浆。The Beikengchang molybdenite and polymetal deposit in Zhangping City is located on the eastern part of the Late Paleozoic depression of the southwestern Fujian Province which has experienced the strong tectono-magmatic process with multi-phase mineralization since Mesozoic. The previous isotopic chronological data in the southwestern Fujian Province indicated that there were mineralization during Early and Middle Jurassic and Early Cretaceous,but lack of the mineralization chronological record related to the Late Jurassic magmatism. This paper selected molybdenites from the Beikengchang deposit of Zhangping City to study the Re-Os isotopic chronology. The Re-Os dating result combining with the country rock alteration and the relationship between deposit and intrusion indicates that the molybdenite minerlization experienced several phases,in which the small scale Mo mineralization occurred at 148.8±2.2 Ma.The main Mo mineralization,characterized by the thin vein and net vein bearing inside sandstone of the Lower Permian Cuipingshan Formation,was dated at the isochrone age about 139.8±2.3-143.7±2.1 Ma,representing Late Jurassic and Early Cretaceous mineralization event. And the mineralization material originated from Late Jurassic granite magma in the southwestern Fujian formed after transformation from the Tethyan to Pacific domain.

关 键 词：RE-OS同位素年龄 辉钼矿 北坑场钼多金属矿 福建漳平 

分 类 号：P597.3[天文地球—地球化学]