| 从藏南陆-陆碰撞带深部结构构造演化探讨斑岩铜矿的成岩成矿问题 |
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| 关键词:deep structure of continent-continent collision belts in southern Tibet Gangdise porphyry copper belt clastation and delamination of lithosphere mantle partial melting layer of the crust middle velocity layer between crust and mantle |
| 基金项目:中国地质调查局项目“青藏高原深部过程与资源环境效应研究”(编号: 1212011220903) |
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| A Discussion on the Regional Tectonic-magmatic Activity and the Metallogensis of Gangdise Porphyry Copper Belt Based on the Deep Structure of Continent-continent Collision Belt in Southern Tibet |
| Based on deep imaging results of India and Eurasia collision belt by INDEPTH project, this paper deals with the metallogenic problem of the Gangdise porphyry copper belt in south Tibet continent-continent collision belt from the perspective of structural evolution. Gangdise continental margin was modified by the subduction of Neo-Tethys Ocean lithosphere and then remodified by the continent-continent collision. Deep structure of the collision belt shows the following characteristics: (1) Neo-Tethys Oceanic plate subducted continuously at about 120 Ma, and formed the Gangdise epicontinental volcanic arc, which resulted in the thickening of the crust and brought a large amount of mantle fluid material into thickened crust. (2) Some residual oceanic crust, juvenile lower crust and probably mantle material were existent beneath the collision zone. (3) The Indian lithospheric mantle extended northward under and across the collision zone without any break off. (4) A large partial melting layer (or magma chamber) at the depth of 20 km existed across the Gangdise block, after the initiating of Gangdise thrust at about 10 Ma that, which began to supply the magma with copper; in addition, a layer of middle velocity existed between the crust and the mantle. In the upper crust there were large thrust systems and a backthrust. (5) The formation of multiple sets of thrusts and faults with the collision compression in the Gangdise belt triggered the ore magma activity again, which rose to generate porphyry copper deposits. (6) The surface suffered strong weathering denudation and made the deposit exposed on the surface. |
| ZHAO Wen-jin.2016.A Discussion on the Regional Tectonic-magmatic Activity and the Metallogensis of Gangdise Porphyry Copper Belt Based on the Deep Structure of Continent-continent Collision Belt in Southern Tibet[J].Acta Geoscientica Sinica,37(1):7-24. |
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