本文選題：廣西博白三叉沖　切入點：復式花崗巖體　出處：《成都理工大學》2015年碩士論文　論文類型：學位論文

【摘要】：廣西博白三叉沖鎢礦位于廣西陸川米場-博白三灘多金屬成礦帶內(nèi),此成礦帶隸屬于廣西博白-岑溪多金屬成礦帶的一部分,總體上屬于欽杭成礦帶的西南段。三叉沖鎢礦與礦區(qū)燕山期三叉沖復式花崗巖體有密切的成因關(guān)系,本文對三叉沖復式巖體和三叉沖鎢礦床進行了詳細研究,重點探討了三叉沖復式巖體的地球化學性質(zhì)、巖漿演化及其與三叉沖鎢礦床之間的成因關(guān)系。提出了三叉沖鎢礦體主要產(chǎn)于巖體與奧陶系中統(tǒng)東沖組(O2d)含灰?guī)r地層的接觸帶內(nèi)的矽卡巖體礦化體中,該礦床屬于典型的矽卡巖鎢礦床,受F5斷層控制,礦體呈似層狀、脈狀產(chǎn)出。圍巖蝕變有云英巖化、矽卡巖化、角巖化、硅化等。根據(jù)鋯石U-Pb同位素測年,可將礦區(qū)出露的三叉沖復式花崗巖體可分為兩種時代,即主體花崗巖體與補體花崗巖體。其中主體的巖性為中粒黑云母花崗巖,巖體形成時代約為105Ma,補體的巖性為細粒二云母花崗巖,巖體形成時代約為103Ma。三叉沖復式花崗巖體為早期白堊紀的晚期巖漿作用的產(chǎn)物。細粒二云母花崗巖的Na2O和K2O演化趨勢巖明顯不同于中粒黑云母花崗;且具有更高的CaO和Sr含量;并且,細粒二云母花崗巖的La/Lu比值更高。這些證據(jù)證明細粒二云母花崗巖并非中粒黑云母巖通過分離結(jié)晶形成,而是玄武巖質(zhì)巖漿底侵下地殼,引起基底巖石發(fā)生新的一次部分熔融的產(chǎn)物,并與幔源基性巖漿發(fā)生混合作用后形成的。根據(jù)野外地質(zhì)調(diào)查、礦床學、巖石學及地球化學證據(jù),三叉沖鎢礦床在成因上與三叉沖復式巖體中的細粒二云母花崗巖密切相關(guān);三叉沖鎢礦床是由三叉沖復式巖體巖漿熱液活動引發(fā)的,同時受北東向斷裂造和地層的聯(lián)合控制形成的矽卡巖型鎢礦床。三叉沖鎢礦床成礦年齡應該在103Ma或者略為晚點,為早白堊世晚期。
[Abstract]:Bobai Sanchachong tungsten deposit in Guangxi is located in the polymetallic metallogenic belt of Michang-Bobai Santan in Luchuan, Guangxi, which belongs to a part of the polymetallic metallogenic belt of Bobai and Cenxi in Guangxi. Generally speaking, it belongs to the southwestern section of the Qinghang metallogenic belt. There is a close genetic relationship between the Sanjiachong tungsten ore deposit and the Yanshanian Triford-thrust composite granite body in the mining area. In this paper, a detailed study has been carried out on the Sanchangchong complex rock mass and the Sanjianchong tungsten ore deposit. The geo-chemical properties of the trichromatic composite rock mass are discussed in detail. The evolution of magma and its genetic relationship with the Sanjianchong tungsten deposit. It is suggested that the Sanjianchong tungsten orebody mainly occurs in the skarn mineralization in the contact zone between the rock body and the Ordovician middle Ordovician Dongchong formation (O2d) limestone bearing strata. The deposit is a typical skarn tungsten deposit, controlled by F5 fault, and the orebody is stratiform and vein-like. The surrounding rock is altered by quartz, skarn, hornstone, silicification, etc. According to zircon U-Pb isotopic dating, It can be divided into two ages: the main granite body and the complement granite body, in which the lithology of the main body is medium-grained biotite granite. The age of formation of the rock body is about 105 Ma.The lithology of the complement is fine-grained dimite granite. The age of formation of the granites is about 103 Ma.These granites are the product of the late Cretaceous magmatism. The Na2O and K 2O evolution trend rocks of the fine-grained dimicite granites are obviously different from the medium-grained biotite granitic granites and have higher CaO and Sr contents. Moreover, the La/Lu ratio of the granites is higher than that of the granites. These evidences indicate that the granites are not formed by the separation and crystallization of the mesomorphic biotite, but are basaltic magmatic submergence into the lower crust. Resulting in a new partial melting of the basement rock and mixing with the mantle derived basic magma. According to the field geological survey, evidence of ore deposit, petrology and geochemistry, The Sanjianchong tungsten deposit is closely related to the fine-grained dimicite granite in the tri-thrust complex rock mass, which is caused by the magmatic hydrothermal activity of the tri-thrust complex rock mass, the Sanjianchong tungsten ore deposit is closely related to the fine-grained dimicite granite in the tri-thrust complex rock mass. At the same time, the skarn type tungsten deposit formed by the combination of NE fault and strata. The mineralization age of the Sanjianchong tungsten deposit should be at 103 Ma or slightly later, and it is late in the early Cretaceous.
【學位授予單位】：成都理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P618.67

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