陕西省凤太矿集区二里河铅锌矿床的成矿时代：来自闪锌矿Rb-Sr同位素年龄的证据  

Ore-forming time of the Erlihe Pb-Zn deposit in the Fengxian-Taibai ore concentration area,Shaanxi Province:Evidence from the Rb-Sr isotopic dating of sphalerites

作　　者：胡乔青[1,2] 王义天[2] 王瑞廷 李建华 代军治 王双彦 

机构地区：[1]地质过程与矿产资源国家重点实验室,中国地质大学地球科学与资源学院,北京100083 [2]中国地质科学院矿产资源研究所,国土资源部成矿作用和资源评价重点实验室,北京100037 [3]西北有色地质勘查局,西安710054 [4]西北有色地质勘查局717总队二里河铅锌矿,宝鸡721004

出　　处：《岩石学报》2012年第1期258-266,共9页Acta Petrologica Sinica

基　　金：中央级公益性科研院所基本科研业务费专项资金项目(K0801);国家“十一五”科技支撑计划课题(2006BAB01A11)联合资助

摘　　要：八方山-二里河铅锌矿床位于陕西凤县-太白(简称凤太)矿集区西北部,矿体主要产于中泥盆统古道岭组与上泥盆统星红铺组接触带中,受NWW向八方山-二里河背斜控制。本次工作对二里河铅锌矿床主成矿阶段的闪锌矿进行了Rb-Sr同位素测年研究,获得了等时线年龄为220.7±7.3Ma,表明矿床形成于晚三叠世,该年龄对于整个凤太矿集区的铅锌成矿时代具有同样约束意义。闪锌矿的87Sr/86Sri值为0.714145±0.000031,指示成矿物质可能主要来源于大陆壳。结合前人的研究成果分析认为,二里河铅锌矿床是凤太矿集区在印支期区域性强烈的构造-岩浆-成矿作用过程中的产物。The Bafangshan-Erlihe Pb-Zn deposit is located on the northwest of the Fengxian-Taibai（abbreviated Fengtai）ore concentration area,and the orebodies mainly occur at the contact zone between the Gudaoling Formation of Middle Devonian and the Xinghongpu Formation of Upper Devonian,controlled by NWW-trending Bafangshan-Erlihe anticline.In this paper,the Rb-Sr isotopic dating is carried out on the sphalerite from the main mineralization stage of the Erlihe Pb-Zn deposit,yielding an isochron age of 220.7± 7.3Ma,showing that the deposit formed in Late Triassic,and the age data is also a constraint on the Pb-Zn ore-forming time of the whole Fengtai ore concentration area.The 87 Sr/ 86 Sri value of the sphalerite is 0.71 41 45±0.000031,indicating that the ore-forming materials are mainly derived from the continental crust.In the context of regional geology,we suggest that the Erlihe Pb-Zn deposit is the product of the regional intensive tectono-magmatic-mineralization processes developed in the Fengxian-Taibai ore concentration area in Triassic.

关 键 词：Rb-Sr同位素测年 成矿时代 铅锌矿床 八方山-二里河 凤太矿集区 

分 类 号：P618.42[天文地球—矿床学] P618.43[天文地球—地质学]