摘要:
经过初步工作,在西藏中冈底斯成矿带发现极具潜力的铍矿找矿线索。新发现的铍矿化体赋存在侵位于古生代地层的粗粒状和伟晶状二云母花岗岩中,岩体和岩脉即为矿化体,并与围岩具有截然的界线。围岩发育热液蚀变和热变质,包括角岩化、硅化、电气石化、石榴子石化、红柱石化、堇青石化等,但分带不甚明显,矿化体和围岩间还发育有"云母线"。矿化体罕见黑钨矿和锂辉石,萤石较少,主要为铌钽矿物和含铍矿物。这一新发现丰富了中冈底斯成矿带新矿种和新的矿床类型,对更加深入地认识冈底斯成矿带构造-岩浆演化与成矿作用、丰富和完善青藏高原南部碰撞造山与成矿理论有重要意义。
关键词:
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中冈底斯成矿带
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新发现
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铍矿
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西藏
Abstract:
The potential clues for beryllium mineralization are newly found in the middle part of the central Gangdise metallogenic zone, Xizang. The beryllium-mineralized bodies herein are hosted in the coarsely granular and pegmatoid two-mica granites emplaced in the metamorphic Palaeozoic strata, occur as rock bodies and rock veins, and are well-defined with the wall rocks. There occur in the wall rocks both hydrothermal alteration and thermal metamorphism, including hornfeldsization, silicification, tourmalinization, garnetization, andalusitization and cordieritization. The "mica line" is also observed between the beryllium-mineralized bodies and wall rocks. The minerals wolframite and spodumene are scarce in the beryllium-mineralized bodies, with additional a small amount of fluorite. The economic minerals include niobium-tantalum minerals and beryllium-bearing minerals. The discovery in this study has revealed that there is a great prospecting potentiality not only for lead, zinc, iron, molybdenum and gold deposits, but also for beryllium deposits in the central Gangdise metallogenic zone. Furthermore, this discovery also has an important geological significance to the better understanding of the tectonicmagmatic evolution and mineralization, collision and mountain building and metallogenesis in the southern part of the Qinghai-Xizang Plateau.
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