Study On The Geological Characteristics Of The Polymetallic Ore Body In Jiama, Tibet

Jiama mining area located in the eastern part of the Gangdise, Gangdese Nyainqentanglha to body, was nearly EW trending, extensional environment are widely developed North West to the secondary faults. In the regional tectonic position, Jiama mining area adjacent to the Himalaya tectonic suture zone edge, located in island arc magmatite belt. The metallogenic condition is favorable and the ore forming prospect is wide.Over half a century, Scholars at home and abroad have carried out a lot of scientific research or production work in the deposit and have fruitful results.. After years of exploration, the Jiama mining area has proven deposits of copper resources of more than 600 million tons, molybdenum resources in the amount of more than 60 million tons, lead and zinc resources more than 50 million tons, associated gold more than 140 tons, associated silver more than 8000 tons, amounted to more than 1500 million tons of equivalent amount of copper resources, Jiama copper polymetallic deposit has undoubtedly become a shining pearl of the world mining industry.After more than half a century of development, the formation of a large number of Jiama mining area practical exploration and theoretical research results, but the Jiama deposit formation is still a hot topic of discussion in the field of geology, some scholars believe that the Jiama is lead zinc copper deposit formed exhalative sedimentation; another part of the scholars that the Jiama is associated with hydrothermal porphyry skarn copper polymetallic deposit, Lhasa is to stretch the body to the north and South-North East, resulting in the deep crust and mantle magma intrusion and the formation of. Therefore, in-depth study of the characteristics of geological elements Jiama, it is necessary to study on the genesis of the deposit, the jiama.Based on the geologic features of Jiama mining area and the relationship between the characteristics of comprehensive, practical field work, the following conclusions are obtained:1, Through the analysis of the geological characteristics of the elements. The findings are as follows: 1) Jiama intrusive rocks is developed. Mainly distributed in the middle of the mining area, veins and North and south two magmatic emplacement channel, the North Branch of the intrusive rocks are approximate NW-SE to erect lens shaped rock, have no bottom, South Branch to approximate the shape of a column barrel rock, North tilt steep angle of penetration bit; 2) mining slate less, mainly on the east side of the north of the mining area and the periphery of the mining to the trend became thick and deep formation as a whole is broken, veins is developed has generally obvious characteristics of silicified; 3) mining hornfels is widely distributed and protolith linbuzong formation sandy slate, with the significant features of the silicide formation as a whole is broken, the thickest hornfels distribution in the vicinity of the central North and south of the mining area, to the surrounding gradually dispersed, with obvious magmatic emplacement and the mining structure transformation characteristics, hornfels roof surface more smooth and engineering control degree good, reflect the actual characteristics of geological elements. According to occurrence characteristics of hornfels, we can infer the taconite mining deep heat source, but the strength of thermal effect is limited, failed to mining area of sandy slate hornfels formation by the obvious characteristics of the late tectonic activity damage, veins and erosion of variable development; 4) carbonate rocks and derivatives is one of the most important parts of geological elements Jiama mining area, the skarn and marble are formed by metamorphic limestone bottom, can significantly distinguish the interlaminar fracture zone exists in the top and bottom traces of strata, skarn fragmentation degree is much higher than the limestone and marble, influenced by tectonic activity and late push nappe tectonics; 5) orebody is widely distributed, mainly for the veins, and the hydrothermal activity closely, terrain and in acid intrusive rock influence; 6) scattered other geological elements in the ore district, such as broken belt, corrosion belt, quartzite, is mainly distributed in the area affected by strong tectonic activity, tectonic activities control and related geological effect.2, Through the relationship on the geological characteristics of elements in the analysis, found that: 1) of Jiama mining area has two fluid channels, affected by the factors of formation, control the mining area north and south two intrusive rock and hydrothermal channels of distribution, the channel of the North Branch of the main control output characteristics of shallow fluid, main channel of the south branch control deeper fluid characteristics; 2) the distribution of geological elements of mining area has NW-SE zonal distribution characteristics, but in the vicinity of the fluid channel. This is obviously influenced by the intermediate acid intrusive rocks of the impact; 3) mineralization geological elements are widely distributed, the mineralization characteristics, mostly disseminated mainly, it can be inferred that the Jiama deposit is epithermal affected by tectonic action in the mineralization is the main mineralization; 4), carbonate rock hornfels and derivatives, in acid intrusive rock is the main mining area of Fu the ore bearing strata, based on the analysis of the relationship between output factors and the characteristics of mine geological elements, that there is a certain relation between the Jiama deposit contact metasomatic mineralization, and magma activity in low temperature hydrothermal geological activities; 5) mineralization area occurred after magma emplacement, has experienced nappe- hornfels thermal metamorphic magmatic emplacement hydrothermal mineralization stage, through complex geological processes, before the formation of the composite formation of Jiama mining area of the deposit, with the typical characteristics of multi-stage mineralization.3, Through the geological factor analysis, combined with mining exploration data, it is considered that: Jiama deposit is controlled by the Jiama- card army fruit push / gliding nappe systems control, diagenesis and metallogenesis have deformation characteristics; genesis types roughly belongs to the intermediate acid intrusive rocks in the rock mass is Guanzhong- low temperature hydrothermal origin of porphyry- skarn card rock type deposit, with multiple stages and hierarchical characteristics and.4, In the South West of the mine area, the South West and North East sounding have favorable conditions for mineralization, and there is a large prospecting potential.