| 西藏冈底斯中东段矽卡岩铜_铅_锌多金属矿床特征及成矿远景分析 |
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| 引用本文：.2005.Characteristics and metallogenic potential of skarn copper_lead_zinc polymetallic deposits in central eastern Gangdese[J].Mineral Deposits,24(5):508~520 |
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| 基金项目:973项目（2002CB412609） |
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| 中文摘要:冈底斯中东段矽卡岩型铜_铅_锌多金属矿床分为甲马—林周、贡嘎—扎囊—泽当和拉萨—谢通门3个次级矿带或矿集区，区域上呈现出一定的矿化分带，以甲马—林周矿集区为主要分布区。岩矿石的硫、氢、氧、铅同位素特征表明成矿流体和矿质主要为岩浆热液来源。Re_Os同位素测年说明甲马—林周矿集区的矽卡岩成矿集中在中新世15～17 Ma的较窄时间段内，与该区斑岩型铜钼矿具有相似的岩浆_构造控矿条件和深部地球动力学背景，属同一成矿系列。而冈底斯南带矽卡岩矿床可能形成于印度—亚洲板块的主碰撞期。冈底斯中东段具有良好的矽卡岩型铜多金属矿成矿地质、地球化学条件，显示有良好的找矿前景。 |
| 中文关键词:地质学 矽卡岩矿床 斑岩矿床 铜_铅_锌多金属矿床 矿床特征 成矿作用 冈底斯 西藏 |
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| Characteristics and metallogenic potential of skarn copper_lead_zinc polymetallic deposits in central eastern Gangdese |
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| Abstract:The skarn copper_lead_zinc polymetallic deposits are distributed in an EW_striking metallogenic belt some 450 km long and 90 km wide. The metallogenic belt can be divided into three sub_belts, i.e., Lhasa_Xietongmen in the western part of Gandese, Jiama_Linzhou in the northeast and Gongga_Zalang_ Zhedang in the southern part along the Brahmaputra River, with most of the ore deposits located in Jiama_Linzhou sub_belt. The ore deposits show apparent regional zonal distribution. There exist various kinds of polymetallic deposits, such as iron_copper, copper_lead_zinc_(gold_silver), copper_molybdenum_lead_zinc, copper_gold deposits, and independent copper, lead, zinc and iron deposits. The ore_bearing strata consist mainly of Jurassic_Cretaceous marine carbonate strata and carbonate_bearing marine volcanic_detrital strata. The ore_controlling stocks are dominated by small granitic stocks or porphyries belonging to calcic alkaline ～ high_K_calcic alkaline series. Orebodies mainly occur in stock_contact zones and tectonic zones beside stocks. The main ore_controlling structures include interlaminar tectonic zones, stock_contact zones and fracture zones. The ore formation shows notable multistage mineralization characteristics, the copper, lead and zinc sulfides must have been precipitated mainly at the retrograde skarn stage, and the favorable temperatures for ore precipitation range from 160 to 380℃. Sulfur, hydrogen and oxygen isotope studies indicate that the ore_forming fluids and materials were mainly derived from magmatic fluids. The Re_Os isochronic ages of ore deposits in Jiama_Linzhou region are concentrated in a narrow range of 15_17Ma, coincident with the stretching period in the crust after the formation of the main collision belt in Tibet plateau. This implies that the formation of skarn deposits was related to the partial melting at depth and the fluid concentration resulting from the stretching after Indian_Asia plate collision. The skarn deposits and the porphyry copper deposits in this region have similar magmatic_tectonic and metallogenic geodynamic conditions. These two types of ore deposits were formed in the same period and belong to the same metallogenic series. The skarn deposits are characterized by polymetallic association, high grade, great size and high economic value. Central Gangdese has favorable geological and geochemical environments for the formation of skarn deposits. It is concluded that Jima_Linzhou basin along Leqingla, Qulong, Jiama and Bangpu might constitute a potential metallogenic area dominated by skarn_type copper_lead_zinc polymetallic deposits. |
| keywords:geology, skarn deposit, porphyry deposit, copper_lead_zinc polymetallic deposit, geological characteristics of ore deposit, metallogeny, Gangdese, Tibet |
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