投稿时间：2017-03-31
修订日期：2017-07-26
网络发布日期：2017-12-28
中文摘要:新疆塔拉特铅锌铁多金属矿床产于阿尔泰南缘克兰火山-沉积盆地中。矿床赋存于上志留统—下泥盆统康布铁堡组的一套变质酸性火山碎屑岩中，铁、铅锌的资源量均已达到中型规模以上。矿床中发育显著层状、纹层状矿化，具有喷流沉积成矿特征，同时以铅锌为主的透镜状、脉状矿化，及相关的矽卡岩化、硅化等热液蚀变也非常普遍。在脉状矿体边部角闪石化热液蚀变中采集少量热液成因细脉浸染状辉钼矿，及同期脉状矿体中的黄铁矿和闪锌矿，对脉状铅锌矿体中黄铁矿、闪锌矿样品开展Rb-Sr测年，对辉钼矿样品开展Re-Os测年研究。同位素测年结果表明，5件硫化物的Rb-Sr等时线年龄为（246.2±3.7）Ma，4件辉钼矿Re-Os同位素等时线年龄为（266±14）Ma，加权平均年龄为（250.8±3.1）Ma。综合考虑测年结果一致性以及精度可靠性，认为热液蚀变及脉状矿化可能发生在246~251 Ma，暗示塔拉特多金属矿床的形成很可能经历了二叠纪晚期的一期成矿热事件，同时也限定了该矿床最终形成早于晚二叠世。辉钼矿样品中w（Re）为216.7×10-6~277.5×10-6，黄铁矿和闪锌矿中初始87Sr/86Sr值介于0.710 19~0.710 31之间，平均值为0.710 25，指示辉钼矿、黄铁矿及闪锌矿成矿物质来源具有幔源特征。17件硫化物样品δ34SV-CDT值范围变化于-11.7‰~2.4‰，分为2组，一组为峰值在-10‰附近的负值，一组为0值附近的正值，说明成矿物质硫可能与海水中的生物作用及深源岩浆硫有关。以上研究表明，塔拉特铅锌铁矿床为晚志留世—早泥盆世的喷流沉积与后期二叠纪的岩浆热液蚀变叠加成矿作用的产物。
Abstract:The Talate Pb-Zn-Fe polymetallic deposit occurs in Kelan volcanic-sedimentary basin of southern Altay, with the host rocks being Upper Silurian-Lower Devonian Kangbutiebao Formation, and now it is a middle-size deposit. The orebodies are mainly layered and stratoid in form which is a feature of submarine exhalation-sedinentation, and it is common that the appearance of Pb-Zn orebodies is veined and lenticular in relation to skarnization and silicfication. A little veinlet-disseminated molybdenite occurs in amphibole-altered rocks around the veined orebodies. The results show that the Re-Os isochron age of four samples is (266±14) Ma, and the weighted mean ages are (250.8±3.1) Ma. The Rb-Sr isochron age of pyrite and sphalerite is (246.2±3.7) Ma. According to the accuracy, the result means that some metallogenic events might have occurred during 246~251 Ma, and the main mineralization perhaps took place earlier than Late Permian. The rhenium content of molybdenite samples range from 216.7 to 277.5 μg/g, whereas the initial Sr isotope ratios (87Sr/86Sr)i range from 0.710 19 to 0.710 31, with an average of 0.710 25, which indicates that Mo was derived from the mantle. The values of δ34SV-CDT from 17 sulfide samples are from -11.7‰ to 2.4‰, and can be divided into two groups:one group is negative around -10‰, and the other is positive around 0. The result suggests that the metallogenic materials might have been related to biological effects in deep sea and also might have come from the deep crust. It is thus held that the Talate Pb-Zn-Fe deposit is the product of the volcanic sedimentation and late magmatic hydrothermal alteration.
keywords:geochemistry Re-Os age Rb-Sr age Multi-stage mineralization Talate Pb-Zn-Fe deposit southern Altay
文章编号：
中图分类号：P618.42,P618.43
文献标志码：
基金项目:国家自然科学基金项目（编号：41273017）资助
引用文本：
袁玲玲,刘锋.2017.阿尔泰南缘塔拉特铅锌铁多金属矿床硫化物Re-Os和Rb-Sr年龄及其地质意义[J].矿床地质,36(6):1333~1351YUAN LingLing,LIU Feng.2017.Sulfide Re-Os age and Rb-Sr age of Talate Pb-Zn-Fe polymetallic deposit in southern Altay and their geological significance[J].Mineral Deposits36(6):1333~1351
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