河南省西峡县龙潭沟金矿成矿物质来源及成因探讨

【作者】 王力；

【导师】 胡祥昭；

【作者基本信息】 中南大学 ， 构造地质学， 2009， 硕士

【摘要】 河南省西峡县龙潭沟矿区位于华北板块与扬子板块之间的拼合带—秦岭造山带东段。矿体赋存于黑烟镇花岗岩体与二郎坪群火神庙组地层的内外接触带。通过对龙潭沟矿区岩石化学、微量元素、稀土元素和流体包裹体的分析与研究,结合前人的研究成果,对矿区的成矿物质来源及矿床成因进行探讨。研究认为龙谭沟金矿是一个多期成矿作用形成的金矿床;主要的赋矿地层为二郎坪群火神庙组,区内成矿作用可以分为三个成矿期:早期同生沉积期、中期变质富集期和后期交代热液期。通过对矿区地层、构造、岩浆岩的研究,以及微量元素、稀土元素及流体包裹体分析,认为本区金的成矿物质来源与其成矿时代密切相关。不同的成矿时期,地层、构造、岩浆岩对金矿的形成起不同的作用。在早期同生沉积期,地层中的成矿物质初始富集;中期变质期,地层中的成矿物质被活化,并在局部富集;后期交代热液期,花岗岩体提供成矿物质及热能。研究认为本区的矿化特征与交代热液型矿床极为相似:矿化温度属中低温范围;矿体为脉状,处于低温低压中心,且产于岩体的接触带附近;对矿床围岩的微量元素分析可以得出,矿体周围岩石呈负晕;对包裹体成份分析得出,阳离子类型以Ca-Na型为主。本区的矿床成因属于交代热液型矿床。更多还原

【Abstract】 Longtangou ore deposit in Xixia County of Henan Provnce is situated in the eastern part of Qinling orogenic belt which is located at matching belt between North China platform and Yangze platform. Its ore-body occurred in the endo-or exdo-contact zone of Heiyanzhen granite body and strata of Erlangping Group Huoshenmiao Formation. Based on the study and analysis on petrochemistry, trace element, rare-earth element, fluid inclusion and previous achievements, the ore-forming material origin and the deposit genesis are discussed.The research believes that Longtangou gold deposit experienced a multistage metallogenesis. The main ore-hosted stratum is Erlangping Group Huoshenmiao Formation. The mineralization can divided into three mineralization stages, the erarly syngenetic depositional stage, the midterm metamorphic enrichment stage, and the late hydrothermal metasomatic stage.Based on the study on strata, structure, magmatic rock and race element, rare-earth element, fluid inclusion, it is suggested that the ore-forming material origin may be closely related with the ore-forming time. Different ore-forming time, strata, structure and magmatic rocks take different function on forming gold deposit. In the early syngentic depostional stage, the ore-forming material of strata begin to initial enrich, in the midterm metamorphic enrichment stage, the ore-forming material of strata are activated and enriched in local, and the late hydrothemal metasomatic stage, the granite body provide ore-forming materials and heat.Studies suggest that the mineralization character in this area is very similar to hydrothermal-replacement deposit. Mineralization temperature belongs to medium-low temperature range; the ore-bodies are veined, they are in the center of low temperature and low pressure, and located next to the contact zone of granite body; It can be drawn that the wall rock is negative circle by the analysis of trace element of wall rock; the cation type is the Ca-Na by analysis of inclusion component. The deposit genesis belongs to the hydorthermal metasomatic deposit.更多还原