| 西藏革吉县尕尔穷铜金矿床地质特征及其成因意义 |
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| 关键词:Ga’erqiong Cu-Au deposit geological characteristics metallogenic model genesis |
| 基金项目:公益性行业科研专项(编号: 201011013-3);国家973项目(编号: 2011CB403103) |
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| Geological Characteristics and Genetic Significance of the Ga’erqiong Cu-Au Deposits in Ge’gyai County, Tibet |
| The Ga’erqiong Cu-Au deposit in Ge’gyai County of Ngari area in Tibet is the first large-size Cu-Au deposit based on detailed survey. The ore district has three fractures, in which fractures F1 and F2 are NE-SW trending whereas F3 is NS- extending. The attitude of F1 is very complex, and the extension is longer than 3000 m. The Cu-Au ore body in this fracture zone is strictly controlled by the fracture. The deposit consists of porphyry Mo-(Cu, Au) ore body, skarn Cu-Au ore body in contact zone and IOCG-like Fe-Cu-Au ore body in F1 fracture zone. Different ore bodies have marked differences. Porphyry ore body is mainly developed in quartz diorite and granite-porphyry, in which metallic minerals are mainly stockwork molybdenite, and subordinately chalcopyrite, magnetite, pyrite; the mineral assemblages are composed of magnetite-pyrite and chalcopyrite-molybdenite. The skarn ore body is mainly developed in the zone where quartz diorite and granite-porphyry are in contact with carbonatite, and the shapes are lamellar and lamellar; the main metallic minerals are veinlet-stockwork chalcopyrite, bornite, chalcocite, covellite, native copper, native silver and native gold. The IOCG-like Fe-Cu-Au ore body occurs in F1 fracture zone, its shape is lamellar and the leading metallic minerals are veinlet-stockwork ore and brecciated hematite, magnetite, chalcopyrite, bornite, chalcocite, covellite, native gold; the mineral assemblages are chalcopyrite-native gold, chalcopyrite-bornite-native gold-silver, and hematite-magnetite-native gold. Based on the geological characteristics of the ore deposit in combination with the data available, this paper discusses the geological characteristics of the ore deposit, and holds the view that the Ga’erqiong Cu-Au deposit was formed after the closure of the Bannu Ocean in late Cretaceous period, and by the collision of arc-continent between the southern Qiangtang-Sanjiang complex slab and the Gangdise-Nyanqentanglha slab, showing the tripartite metallogenic characteristics genetically closely related to potassic basalt–high potassic calc-alkaline diorite-lithosome and continent-continent co-collision potassic basalt-high potassic calc-alkaline remelted granite-porphyry. That is to say, the host ore body existed in porphyry, skarn, and structural fracture zone, thus forming the “porphyry-skarn-IOCG-like” Cu-Au deposit. |
| HU Zheng-hua,DING Feng,TANG Ju-xing,LI Zhi-jun,YAO Xiao-feng,DENG Shi-lin,ZHANG Zhi,WANG Yi-yun,WANG Hong-xing,SONG Jun-long,CHEN Wei.2012.Geological Characteristics and Genetic Significance of the Ga’erqiong Cu-Au Deposits in Ge’gyai County, Tibet[J].Acta Geoscientica Sinica,33(4):588-600. |
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