| 柴北缘地区的两类块状硫化物矿床——Ⅱ.青龙滩式VHMS型Cu_S矿床 |
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| 引用本文：.2005.Two types of massive sulfide deposits along northern margin of Qaidam basin, Qinghai Province: Ⅱ. Qinglongtan_style VHMS Cu_S deposits[J].Mineral Deposits,24(6):575~583 |
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| 基金项目:国家科技攻关计划（2003BA612A_07）和国家自然科学基金（40372051） |
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| 中文摘要:文章综述了柴北缘地区的VHMS型Cu_S矿床——青龙滩式矿床，指出其容矿岩石为加里东造山带中被改造过的岛弧火山岩，该矿床中含铜硫化物矿层形成后不但遭受过构造的强烈改造，而且也受后期矽卡岩化的改造和叠加。放射性同位素测年结果表明，青龙滩矿床的主岩——安山岩形成于晚寒武世（514.2±8.5） Ma，后期的矽卡岩矿化大约发生在290 Ma。柴北缘加里东造山带中既产有VHMS型Cu_S矿床（如青龙滩矿床），也产有SEDEX型Pb_Zn矿床（如锡铁山矿床），两者的成矿地质构造背景和形成年龄不相同。柴北缘地区的早古生代洋（海）盆于晚寒武世俯冲消减，出现岛弧，并形成青龙滩等VHMS型Cu_S矿床，之后（早奥陶世），发生弧后拉张，形成弧后盆地及锡铁山等SEDEX型铅锌矿床。 |
| 中文关键词:地质学 VHMS型Cu_S矿床 青龙滩式 柴北缘 |
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| Two types of massive sulfide deposits along northern margin of Qaidam basin, Qinghai Province: Ⅱ. Qinglongtan_style VHMS Cu_S deposits |
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| Abstract:The Qinglongtan_style deposits refer to the VHMS_type Cu_S deposits in island arc volcanic rocks of the Caledonian orogenic belt along the northern margin of Qaidam basin. The copper_bearing sulfide horizon of the Qinglongtan deposit underwent not only intense structural reformation but also superimposition of skarn_type mineralization after the formation of massive sulfide ores. Dating data show that andesite, the host rock of the Qinglongtan deposit, was formed during Late Cambrian 〔(514.2±8.5) Ma〕, and skarn mineralization took place at about 290 Ma. SEDEX Pb_Zn deposits such as the Xitieshan Pb_Zn deposit and VHMS Cu_S deposits such as the Qinglongtan Cu_S deposit occur in this Caledonian orogenic belt, but their geological settings and formation ages are different. The subduction of the Early Paleozoic ocean/sea occurred in Late Cambrian and the island arc was formed in the northern margin of Qaidam basin where the Qinglongtan and other VHMS_type Cu_S deposits occurred. After that, this region was subjected to extension and transformed into a backarc basin, where the Xitieshan and other SEDEX_type Pb_Zn deposits were formed during Early Ordovician. |
| keywords:geology, VHMS_type Cu_S deposits, Qinglongtan_style, northern margin of Qaidam basin |
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