青海纳日贡玛斑岩铜钼矿床地球化学特征及成矿作用  

Geochemical Characteristics and Mineralization of Narigongma Porphyry Cu-Mo Deposit in Qinghai Province

作　　者：智超 廖昆[2] 

机构地区：[1]甘肃有色金属地质勘查局张掖矿产勘查院,甘肃张掖734012 [2]四川省地质矿产勘查开发局物探队,四川成都610000

出　　处：《西北地质》2014年第3期26-34,共9页Northwestern Geology

基　　金：中国地质调查局资源评价项目(12120113088900)资助成果

摘　　要：纳日贡玛矿床是我国著名"三江"北段成矿区带中最典型的斑岩型Cu-Mo矿床。在总结矿床地质特征的基础上,通过系统总结该矿床的矿床地球化学及成矿作用相关资料,得出以下结论:1纳日贡玛矿床形成于喜马拉雅运动早期,纳日贡玛铜钼矿床成矿物质主要来自花岗斑岩体,成矿花岗斑岩源于下地壳;成矿流体为岩浆期后热液,矿床硫是由岩浆硫(为主)和成矿流体萃取围岩中的硫所组成的1种混合硫源。矿床的形成与青藏高原东缘区域构造和应力转换密切相关。2基于已有认识,建立了纳日贡玛铜钼矿床的成矿理想模式,认为矿体形成背景可能为逆冲挤压推覆条件下的局部拉张环境,拉张降压以及围岩的性质导致了该矿床富钼贫铜现况;矿床热液蚀变发育,绢云岩化与矿体较为密切,钾化带范围小,与成矿关系不大;纳日贡玛矿区剥蚀程度大,纳日贡玛矿床东南部剥蚀程度相对较小,在东南部外围找矿过程中,应该兼顾矽卡岩型矿体。The Narigngma deposit is a typical porphyry Cu-Mo deposit located in the north metallogenic belt of Sanjiang Plain. Based on the features of Narigongma deposit, and through a systematic summary of the deposit geochemistry characteristics as well as mineralization information, following results are obtained： （1） The Narigongma deposit formed in the early Himalayan movement. The metallogenic material was mainly composed of granitic porphyry from lower crust. The ore-forming fluids derived from magmatic hydrothermal. The sulfur in the deposit is originated from a mixed sulfur source that consisted of magmatic sulfur （mainly） and the extracted sulfur by ore-forming fluid from the adjacent rock. Deposit formation is related to transformation of regional tectonic and stress of eastern margin of the Tibetan Plateau. （2） Based on the results, an ideal metallogenic model of Narigongma Cu-Mo deposit is established, and it isconsidered that the deposit forming background may be partial extensional environment under thrust nappe squeezed conditions. The tensile antihypertensive and the properties of the surrounding rock caused the current situation of rich-molybdenum and poor-copper. Hydrothermal alteration is developed in the deposit, and sericitization is closely related to ore body, while the potassic alteration range is small, having little relationship with mineralization. The erosion degree of Narigongma mining area is strong, while the erosion degree in southeast of Narigongma deposit is relatively small. So in the peripheral exploration process, we should take into account the skarn-type ore bodies.

关 键 词：矿床地球化学 成矿作用 斑岩铜钼矿 成矿模式 纳日贡玛 青海南部 

分 类 号：P618.41[天文地球—矿床学] P618.65[天文地球—地质学]