| 大厂锡矿床黑色包裹体成因分析及容矿围岩的古地温研究 |
| Received:March 23, 2020 Revised:April 23, 2020 点此下载全文 |
| 引用本文：HAN Fa,TIAN ShuGang,LIU Jian.2020.Research on black inclusions and paleotemperature of ore-hosting rocks in Dachang tin deposit[J].Mineral Deposits,39(3):461~476 |
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| Author Name | Affiliation | | HAN Fa | Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China | | TIAN ShuGang | Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China | | LIU Jian | Department of Geology, Colorado School of Mines, Golden, Colorado, USA |
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| 基金项目:本文为R.W.Huthcinson研究奖学金及Steven HUI奖学金的资助成果 |
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| 中文摘要:在大厂长坡-铜坑矿床，锡石中普遍存在具有代表性的2类包裹体：黑色包裹体和气-液两相的流体包裹体。文章通过对包裹体结构形态和理论分析，证明黑色包裹体是原生流体包裹体在内压超高（overpressured）条件下形成的。通过牙形石色温指数（CAI）及表面残余结构的研究，获得了容矿岩石的古地温为300~650℃，与前人通过气-液两相包裹体获得的矿化温度（240~540℃）高度吻合，说明容矿围岩的受热事件与同期矿化事件，其热源具有同源性，可能来自矿床下伏的燕山期花岗岩。层状主矿体锡石中原生的流体包裹体正是在这期事件的影响下，变成了黑色包裹体。这些研究证明，大厂锡矿至少有早、晚2期成矿作用。黑色包裹体的发现和古地温的恢复，为层状主矿体是在海底热液喷流沉积成因的认识提供了关键证据。 |
| 中文关键词:地球化学 黑色包裹体 成因分析 指示意义 牙形石 古地温 矿床成因 |
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| Research on black inclusions and paleotemperature of ore-hosting rocks in Dachang tin deposit |
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| Abstract:In the Dachang Changpo-Tongkeng deposit, there are two typical types of inclusions in the cassiterite:black inclusions and gas-liquid two-phase fluid inclusions. Black inclusions were formed under overpressure condi-tions. Research on the CAI of the conodonts and the residual structure on their surface shows that the paleotem-perature of the ore-hosting rocks is 300~650℃. By researching on the gas-liquid two-phase inclusions, previous studies have obtained a mineralization temperature of 240~540℃. The two sets of temperatures are very consis-tent, indicating that the heating event of the ore-hosting rocks and the ore-forming process are homologous in terms of thermal source; that is, the Yanshanian orogeny granite underlying the deposit. The primitive fluid inclu-sions in the cassiterite of the layered main orebodies became black inclusions under the influence of the heat source in this period. Evidently, the deposit has at least two stages of metallogenesis. The discovery of the black inclusions provides reasonable evidence for understanding the cause of formation of the layered main orebodies as ancient sea-floor hydrothermal exhalation-sedimentary deposits. Conversely, it is incorrect to interpret all possi-ble metallogenic geological processes of the deposit using the existence of gas-liquid two-phase fluid inclusions. |
| keywords:geochemistry black inclusions implication CAI of the conodonts paleotemperature origin of the ores |
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