| 王登芳.西藏知不拉和浪母家果矽卡岩铜矿地质特征及驱龙-知不拉-浪母家果成矿系统的确定[J].地质与勘探,2015,51(4):619-633 |
| 西藏知不拉和浪母家果矽卡岩铜矿地质特征及驱龙-知不拉-浪母家果成矿系统的确定 |
| Geological Characteristics of the Zhibula and Langmujiaguo skarn Cu deposits and the determination of the Qulong-Zhibula-Langmujiaguo porphyry-skarn mineralization system in Tibet |
| 投稿时间：2014-12-29 修订日期：2015-03-16 |
| DOI： |
| 中文关键词: 斑岩-矽卡岩成矿系统 驱龙巨型斑岩铜钼矿 冈底斯 西藏 |
| 英文关键词: Porphyry-skarn mineralizing system, Qulong giant porphyry Cu-Mo deposit, Gangdese, Tibet |
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| 中文摘要: |
| 西藏驱龙巨型斑岩铜钼矿床周围产出有知不拉与浪母家果矽卡岩铜矿。研究通过揭示知不拉和浪母家果的地质特征、成矿侵入体的地球化学特征和硫同位素特征，结合前人的年代学资料，确立两者与驱龙斑岩铜矿共同构成斑岩-矽卡岩成矿系统。结果显示知不拉与浪母家果矽卡岩矿床中的侵入岩地球化学特征与驱龙矿区的侵入岩地球化学特征相似，属于准铝质、钙碱性-高钾钙碱性岩石；稀土元素表现为强烈的LREE和HREE的分异，除知不拉的细晶岩有很强的Eu负异常，其他具有很弱的Eu负异常；明显富集大离子亲石元素(LILE)和高场强元素(HFSE)，K、Pb的正异常，Ta、Nb、Ti的负异常。知不拉硫化物硫同位素与驱龙斑岩铜钼矿的硫同位素相比有明显的差异，这样的差异可能是由于成矿热液氧逸度的变化和晚期高δ34S值的天水加入造成的。研究确立驱龙-知不拉-浪母家果斑岩-矽卡岩成矿系统，主要基于：时代相近，空间毗邻；驱龙斑岩铜矿花岗闪长岩接触带发育有明显矽卡岩矿化；与矿化有关的侵入岩地球化学特征相似性；成矿物质演化趋势相似；矽卡岩连续演化的物理化学条件。而钙质围岩、多期次侵位且侵位较浅的岩浆与区域内构造活动及矿区内断裂、裂隙发育，共同决定了斑岩-矽卡岩系统的产出。 |
| 英文摘要: |
| The Zhibula and Langmujiaguo skarn Cu deposits are adjacent to the Qulong giant porphyry Cu-Mo deposit, Tibet. Combined with previous studies on the Qulong deposit, this work analyzes the geological characteristics, geochemistry of intrusions and sulfide sulfur isotopic composition of the both skarn deposits. Our objective is to determine the relationship between the Qulong and the two skarn deposits. The results suggest that the geochemistry of Zhibula and Langmujiaguo intrusions is similar to Qulong, belonging to metaluminous, calc-alkaline to high K calc-alkaline composition. REE patterns show strong enrichments in light REE relative to heavy REE and weak negative Eu anomalies, except Zhibula aplite. These intrusions are also enriched in large ion lithophile elements, K and Pb, and depleted in high-field strength elements, Nb, Ta and Ti. The sulfur composition of the two skarn deposits is apparently different from Qulong, which might resulted from the change of oxygen fugacity and the involvement of high δ34S value in the late stage of skarn mineralization. We set up the Qulong-Zhibula-Langmujiaguo porphyry-skarn mineralization system based on: 1) geochronologic similarity and spatial location; 2) the observation of skarn mineralization in the contact between Qulong granodiorite and Jurassic Yeba tuff; 3) the similar geochemical compositions of intrusions in Qulong, Zhibula and Langmujiaguo; 4) the similar evolving trend of ore materials, specially sulfur; and 5) the successive physicochemical conditions of both skarn deposits. We suggest that the calcic wall-rock, multiple-stage shallow intrusions, and the development of regional and deposit faults and fissures are the factors controlling the occurrence of porphyry-skarn mineralization system. |
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