青海祁漫塔格楚阿克拉千隐爆角砾岩型铅锌矿床成矿模式及发现意义

    Metallogenic model and discovery significance of the Chuakelaqian cryptoexplosion breccia type Pb-Zn deposit in the Qimantag metallogenic belt, Qinghai Province

    • 摘要: 青海省东昆仑成矿带西段的祁漫塔格地区与三叠纪花岗岩、斑岩有关的斑岩型、接触交代矽卡岩型、热液型矿产广泛分布。近年以缺位预测成矿理论为指导,在祁漫塔格发现了一处新类型矿床——楚阿克拉千隐爆角砾岩型铅锌矿床。开展了流体包裹体和氢、氧、硫同位素研究,结果表明矿床内存在明显的2类流体,一类为中高温低盐度低密度NaCl-CO2-H2O流体,另一类为低温中等盐度中低密度NaCl-H2O流体,2类流体反映的成矿压力明显不同,与隐爆作用吻合,压力的突然释放是成矿的关键。氢、氧同位素结果表明,成矿热液来源于岩浆水和大气降水的混合,硫同位素显示硫来源于岩浆。对矿床特征分析总结,综合认为,矿床的形成与斑岩活动密切相关,结合卡尔却卡A区斑岩成矿特征,建立了楚阿克拉千矿床成矿模式,提出了楚阿克拉千地区具有斑岩型找矿潜力的认识。该矿床的发现对于促进东昆仑地区斑岩找矿突破和斑岩成矿规律研究具有重要的科学意义和勘查意义。

       

      Abstract: There are many skarn, hydrothermal and porphyry type deposits which are closely related to Triassic granite and porphyry in Qimantag area of western East Kunlun metallogenic belt, Qinghai Province.A new type deposit, i.e., Chuakelaqian cryptoexplosion breccia type lead-zinc deposit, was discovered recently by vacancy prediction metallogenic theory.Based on a study of fluid inclusions and H-O-S isotopes, the authors found that there were two kinds of fluids in the Chuakelaqian deposit.One was middle-high temperature low salinity low density NaCl-CO2-H2O fluid and the other was low temperature middle salinity middle-low density NaCl-H2O fluid.Metallogenic pressures of two types of fluids were different.This coincides with the key of cryptoexplosion and mineralization that pressure is suddenly released.Ore-forming fluids originated from the mixing of magmatic and meteoritic water and S originated from magmatic activity.Based on summary of deposit characteristics, it is considered that the deposit was closely related to porphyry. The metallogenic model of the deposit was built up in combination with porphyry metallogenic characteristics of A area in the Kaerqueka deposit. The opinion that there exists large potential in prospecting for porphyry type deposits in the Chuakelaqian area was put forward. The discovery of this deposit has important scientific and exploration significance for promoting the breakthrough of porphyry prospecting and the study on metallogenic regularity of porphyry in Eastern Kunlun area.

       

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