| 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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| 引用本文：雷传扬,李志军,张志,胡正华,王红星,宋俊龙.2012.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[J].地球学报,33(4):601-612. |
| DOI：10.3975/cagsb.2012.04.20 |
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| 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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| 中文摘要:尕尔穷铜金矿位于念青唐古拉板片与南羌塘板片之间的班公湖-怒江缝合带西段, 区内花岗岩类形成于燕山晚期, 主要为中酸性侵入岩, 以岩基、岩株、岩枝、岩脉等形态产出。岩石具有较低的SiO2(52.92%～79.21%, 多数集中在60%~65%, 平均为63.64%)和较高的Al2O3(10.43%～16.49%, 平均为15.23), 高碱(ω(Na2O+K2O): 4.86%～7.15%), ω(Na2O)/ω(K2O)比值变化较大(0.26～2.26), 弱的负铕异常和负铈异常, 相对富集不相容元素Rb、Th、K、Ce, 而Ba、Ta、Nb、Ti亏损。这些特征表明花岗岩类是准铝质-弱过铝质钙碱性I型花岗岩, 其源区物质可能是基性玄武质成分, 形成于与板块俯冲有关的活动大陆边缘的陆缘弧环境, 为深部地壳物质熔融后与幔源基性岩浆混合作用的产物。 |
| 中文关键词:花岗岩类 地球化学 构造环境 尕尔穷铜金矿 西藏 |
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| Geochemical Characteristics and Geodynamic Significance of the Granites in the Ga’erqiong Cu-Au deposit, Tibet |
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| Abstract: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. |
| keywords:granites geochemical characteristics structural environment Ga’erqiong Cu-Au deposit Tibet |
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