蒙古国额尔登特特大型铜-钼矿床年代学与成因研究  

Geochronology and Origin of the Erdenet Superlarge Cu-Mo Deposit in Mongolia

作　　者：江思宏[1] 聂凤军[1] 苏永江[2] 白大明[1] 刘翼飞[1] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]河南省地质矿产勘查开发局地球物理勘查队,河南郑州450053

出　　处：《地球学报》2010年第3期289-306,共18页Acta Geoscientica Sinica

基　　金：国家科技支撑课题(编号:2007BAB25B02);地质调查项目(编号:1212010911029)联合资助

摘　　要：额尔登特铜钼矿床是20世纪60年代蒙古国发现的一处特大型斑岩型矿床。本文对矿区内的含矿斑岩体-石英闪长岩开展了锆石SHRIMP和LA-MC-ICP-MS同位素测年。分析结果表明,含矿岩体形成时代在240Ma左右,这与矿石中辉钼矿的Re-Os等时线年龄(241.0±3.1Ma,MSWD值为1.02)大体一致,表明成岩成矿作用均发生在早三叠世末至中三叠世初。矿区范围内侵入岩体岩石地球化学研究表明,石英闪长岩、花岗闪长岩和安山岩以及煌斑岩均可能是同源岩浆演化产物,形成于岛弧环境,成岩物质来源较深,可能来自地幔或者熔融的年轻下地壳。硫、铅同位素和锇同位素初始比值显示,成矿物质主要来自含矿侵入岩体,但是也有其它来源。额尔登特斑岩型铜-钼矿床的成矿作用与蒙古-鄂霍次克洋的闭合所导致的构造-岩浆活动有关。The Erdenet ore deposit is a superlarge porphyry Cu-Mo deposit discovered in Mongolia in the 1960＇s.Zircon dating with U-Pd SHRIMP and LA-MC-ICP-MS methods suggests that the host quartz diorite was emplaced at ca.240 Ma,coeval with the ore-forming age（241.0±3.1 Ma,MSWD=1.02）dated by the molybdenite Re-Os isochron.It is thus thought that the main magmatism and mineralization took place at the end of the early Triassic and the beginning of the middle Triassic.Element geochemistry and Nd-Sr isotopes imply that quartz diorite,granodiorite,andesite and lamprophyre intruded under the island arc,and derived their materials from the upper mantle or melted younger lower crust.Sulfur and lead isotopic features and initial Os values suggest that the ore-forming materials were mainly derived from the host quartz diorite and granodiorite.The ore-forming process of the Erdenet porphyry Cu-Mo deposit was related to the subduction resulting from the closure of the Mongolia-Okhotsk ocean.

关 键 词：年代学 含矿岩体 斑岩型铜-钼矿床 额尔登特 蒙古国 

分 类 号：P597.3[天文地球—地球化学] P611.1[天文地球—地质学]