西藏尕尔穷铜金矿床花岗岩类的地球化学特征及其地球动力学意义 |
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关键词:granites geochemical characteristics structural environment Ga’erqiong Cu-Au deposit Tibet |
基金项目:国家973项目(编号: 2011CB403103);中央公益性行业科研专项(编号: 201011013-3);青藏专项(编号: 1212011085529);教育部岩石学矿床学国家重点(培育)学科建设项目(编号: SZD0407) |
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摘要: |
Geochemical Characteristics and Geodynamic Significance of the Granites in the Ga’erqiong Cu-Au deposit, Tibet |
The Ga’erqiong Cu-Au deposit is located in the western segment of the Bangong Co-Nujiang suture zone between Nyainqentanglha slab and South Qiangtang slab, where the granites, composed mainly of middle acid intrusive rocks in the forms of batholith, stock, apophyse and vein, were formed in the Late Yanshanian period. The rock is characterized by comparatively lower SiO2 (52.92%–79.21%, mostly 60%–65%, 63.64% on average) and higher Al2O3(10.43%–16.49%, averagely 15.23), higher alkali(ω(Na2O+K2O): 4.86%–7.15%), ω(Na2O)/ω(K2O) changeable ratio(0.26–2.26), weak Eu anomalies and weak Ce anomalies, comparative enrichment of incompatible elements, such as Rb, Th, K, Ce, and depletion of Ba, Ta, Nb and Ti. The characteristics show that the granite is metaluminous-weak peraluminous calc-alkaline I-type granite, and the source region provenance might have been basic basaltic components formed in the continental marginal arc of active continental margin connected to the plate subduction, being the product of the migmatization of the deep crustal melted mate-rial and the mantle source basic magma. |
LEI Chuan-yang,LI Zhi-jun,ZHANG Zhi,HU Zheng-hua,WANG Hong-xing,SONG Jun-long.2012.Geochemical Characteristics and Geodynamic Significance of the Granites in the Ga’erqiong Cu-Au deposit, Tibet[J].Acta Geoscientica Sinica,33(4):601-612. |
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