东天山卡拉塔格矿集区梅岭铜锌（金）矿床成矿作用

发布时间：2018-07-05 12:02

  本文选题：东天山 + 卡拉塔格矿集区　； 参考：《中国地质大学(北京)》2016年博士论文

【摘要】：卡拉塔格矿集区梅岭矿床位于新疆东天山地区吐哈盆地南缘的古生代卡拉塔格隆起带的核部,在大地构造位置上处于大南湖-头苏泉晚古生代岛弧带中段的火山盆地中,赋存于一套基性-中性-酸性火山岩-火山碎屑岩和次火山岩中,矿体主要由M1号矿体、M2号矿体和M12号矿体组成。梅岭矿床M2号矿体的绢云母~(39)Ar-~(40)Ar同位素年龄为264.7±5.7Ma,矿化蚀变英安玢岩的成岩时代为(317.4±2.6)Ma,M12号矿体的矿化蚀变英安斑岩的成岩时代为313.0±6.5Ma,下盘的紫红色英安岩的成岩时代为317.7±4.4Ma,限定了M12号矿体的成矿时代的下限。M1号矿体和M12号矿体的硫化物的Rb-Sr同位素等时线年龄分别为299.2±2.9 Ma和301.0±3.8 Ma,确定梅岭矿床的成矿时代为石炭纪末期。梅岭矿床中原生流体包裹体类型多为气液两相包裹体,个体较小,气液比较小;流体包裹体均一温度为117~238°C,盐度为2.4%~9.3%,为中-低温、中-低盐度流体;成矿压力为6.8~60.6 MPa,成矿深度约为0.2~2.0 km。流体包裹体气相成分以H_2O为主,成矿流体属H_2O-NaCl体系。成矿流体的δ~(18)O_(H_2O)为-5.75‰~-2.61‰,δD为-135.6‰~-117.2‰,表明成矿流体主要为岩浆水及大气降水的混合水。梅岭矿床M1号矿体主要硫化物的微量元素和稀土元素特征显示其成矿流体为具弱还原性的富Cl流体,晚期成矿流体可能遭受了外来热液的混入。微量元素含量特征及元素对的比值变化表明,梅岭矿床应为岩浆热液成因,但其也受到火山作用叠加改造的影响。围岩δ34S的范围为1.4‰~4.4‰,主要硫化物δ~(34)S值的分布范围为-1.6‰~4.8‰,表明S同位素来源可能为幔源硫和火山岩围岩的混合硫。铅同位素研究结果显示出一定的幔源特征,为岩浆壳幔混合来源。依据前人研究成果,并结合本次的工作成果,建立了梅岭低温热液矿床成矿模型。在总结区域成矿资料的基础上,结合野外地质调查和此次研究成果,提出了在卡拉塔格矿集区和大南湖岛弧带内依据火山机构特征、构造特征、蚀变分带明显等特征是此类矿床的重要找矿标识。
[Abstract]:Meiling deposit is located in the core of the Paleozoic Karatagg uplift in the southern margin of the Turpan-Hami basin in the eastern Tianshan area, Xinjiang, and is located in the volcanic basin in the middle segment of the late Paleozoic island arc belt in Dananhu and Tou Suquan in the tectonic position. It occurs in a set of basic-neutral acid volcanic rocks volcanic clastic rocks and subvolcanic rocks. The orebody is mainly composed of M 2 ore body and M 12 ore body. The sericite ~ (39) Ar-~ (40) ar isotopic age of the M ~ (2) orebody in Meiling deposit is 264.7 卤5.7 Ma.The diagenetic age of orebody M _ 2 ~ (39) Ar-~ (40) ar is 264.7 卤5.7 Ma.The diagenetic age of orebody M _ (2) M _ (12) is 313.0 卤6.5 Ma.The diagenetic age of fuchsia dolomite is 317.7 卤4.4 Ma. The Rb-Sr isochron age of sulfides of M12 orebody and M12 orebody is defined as 299.2 卤2.9Ma and 301.0 卤3.8Marespectively. It is determined that the metallogenic age of Meiling deposit is the end of Carboniferous. In Meiling deposit, the types of fluid inclusions are mainly gas-liquid two-phase inclusions, the individual is smaller, the gas-liquid inclusions are smaller, the homogenization temperature of fluid inclusions is 117 ~ 238 掳C, and the salinity is 2.4C / 9.3, which is medium-low temperature and medium-low salinity fluids. The ore-forming pressure is 6.8 ~ 60.6 MPA, and the ore-forming depth is about 0.2 ~ 2.0 km 路m ~ (-1). The gas composition of fluid inclusions is mainly composed of H _ S _ 2O and the ore-forming fluids belong to H _ S _ 2O -NaCl system. The 未 ~ (18) O _ (H _ 2O) of ore-forming fluid is -5.75 鈥，

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