北祁连东段毛藏寺钼（铜）多金属矿床地质特征与成因研究
发布时间：2018-08-04 21:19
【摘要】：北祁连东段毛藏寺钼(铜)多金属矿床是中国建筑材料工业地质勘查中心甘肃总队在进行“甘肃省天祝县毛藏寺矿区萤石矿详查”工作过程中发现的。截止目前,对该矿床的研究程度较低。矿区位于北祁连加里东期造山带东段冷龙岭地区毛藏寺背斜的近轴部。矿体主要赋存于中奥陶统中堡群(O2z)变质砂岩与似斑状二长花岗岩体(ηγπ)的接触部位,以接触带外侧的矿化明显。矿体呈似层状、透镜状、脉状平行排列。矿石呈脉状、细脉浸染状、斑杂状、网脉状。围岩蚀变大致具分带性:岩体中可粗略的分为钾化带、黄铁-绢英岩化带、青磐岩化带;变质砂岩中发育角岩化。矿区矿石矿物样品S同位素δ34S测定值较集中,变化于0±3‰范围之间,说明了硫来源于深部岩浆。不同矿物间δ34S平均值呈现出辉钼矿→黄铁矿→黄铜矿的递减序列,与硫同位素平衡状态下δ34S值在硫化物中递减序列一致,可大致认为该矿床中的辉钼矿、黄铁矿、黄铜矿处于S同位素平衡状态。样品Pb同位素测定值:206Pb/204Pb比值为:18.274~19.472;207Pb/204Pb比值为:15.594~15.747;208Pb/204Pb比值为:38.397~40.096。相关图解表明铅来源比较复杂,可能来自岩浆并且加入了上地壳成分的混染,与造山作用有关。主成矿阶段形成的石英中流体包裹体的岩相学特征与显微测温结果表明,原生流体包裹体可分为富液两相包裹体、富气两相包裹体、含CO2三相包裹体三种类型。成矿流体为中-低温(集中在175℃~315℃)、低盐度(3~5wt%NaCleqv)、中密度(0.7~0.9g/cm3)的H2O-NaCI-CO2(CH4)流体体系。成矿压力集中在15MPa~28MPa之间,对应的成矿深度为为0.39km~1.06km,属浅成矿床。H-O同位素测试结果表明,成矿流体主要来自于岩浆水,后期加入大气降水的混合。与成矿作用关系密切的似斑状二长花岗岩,为钙碱性系列,强烈富集大离子亲石元素Rb、Th、U、K,而Nb、Ta、P、Ti明显亏损;轻稀土元素相对富集,重稀土元素相对亏损。似斑状二长花岗岩具高Si埃达克质岩石特征。很可能起源于俯冲洋壳部分熔融,并与地幔橄榄岩发生了一定程度的相互作用,源区主要残留物为石榴石(±角闪石)。锆石U-Pb测年表明赋矿岩石(似斑状二长花岗岩)成岩年龄为(440.9±1.8)Ma,侵入时代为晚奥陶世。辉钼矿Re-Os同位素模式年龄为(423.3±6.7)Ma,为中晚志留世,稍晚于似斑状二长花岗岩体的形成时代(晚奥陶世)。毛藏寺钼(铜)多金属矿床应属典型的与浅成斑岩体有关的中-低温热液矿床。形成于晚奥陶-早志留时期北祁连洋洋壳俯冲-陆陆碰撞转换阶段洋壳的持续俯冲作用。
[Abstract]:The Mozangsi molybdenum (copper) polymetallic deposit in the eastern segment of North Qilian was discovered in the course of "detailed investigation of Fluorite deposits in Maozangsi Mining area, Tianzhu County, Gansu Province" by Gansu General team of China Building Materials Industry Geological Survey Center. So far, the degree of research on the deposit is relatively low. The mining area is located near the axis of the Maozangsi anticline in the Lenglongling area of the eastern section of the Caledonian orogenic belt in North Qilian. The orebody mainly occurs in the contact site between metamorphic sandstone and porphyry monzogranite (畏 纬 蟺) in the Middle Ordovician Zhonghu Group (O _ 2z), and the mineralization outside the contact zone is obvious. The orebodies are layered, lenticular and veined parallel. The ore is veined, variegated and reticulate. The alteration of the surrounding rock is roughly zonation: the rock mass can be roughly divided into the potash zone, the Huang Tie-sericite zone, the Qingiranlitization zone, and the keratology developed in the metamorphic sandstone. The S isotope 未 34 S values of ore samples in the mining area are concentrated and vary in the range of 0 卤3 鈥，
本文编号：2165182
[Abstract]:The Mozangsi molybdenum (copper) polymetallic deposit in the eastern segment of North Qilian was discovered in the course of "detailed investigation of Fluorite deposits in Maozangsi Mining area, Tianzhu County, Gansu Province" by Gansu General team of China Building Materials Industry Geological Survey Center. So far, the degree of research on the deposit is relatively low. The mining area is located near the axis of the Maozangsi anticline in the Lenglongling area of the eastern section of the Caledonian orogenic belt in North Qilian. The orebody mainly occurs in the contact site between metamorphic sandstone and porphyry monzogranite (畏 纬 蟺) in the Middle Ordovician Zhonghu Group (O _ 2z), and the mineralization outside the contact zone is obvious. The orebodies are layered, lenticular and veined parallel. The ore is veined, variegated and reticulate. The alteration of the surrounding rock is roughly zonation: the rock mass can be roughly divided into the potash zone, the Huang Tie-sericite zone, the Qingiranlitization zone, and the keratology developed in the metamorphic sandstone. The S isotope 未 34 S values of ore samples in the mining area are concentrated and vary in the range of 0 卤3 鈥，
本文编号：2165182
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