Study Of Mineralization Environment And Mineralization Characteristics Of The Donggou Copper Deposits In Qilian County, Qinghai Province

North Qilian orogenic belt is most important province of massive sulfide deposit in China and the world. In the last decade, the establishment and improvement of the North Qilian Early Paleozoic trench-arc-basin system by research group led by Lin-Qi Xia provided a theoretical basis with prospecting in north Qilian mountains. The VHMS related to marine volcanic have characteristics spatial distribution of the clusters, the typical sub-focus, mineralization that has many of times, multi-phase material characteristics. Constraints due to natural conditions, Donggou copper have been less studied, and there are different perceptions on its formation environment and metallogenetic epoch affected the deposit prospecting work.In this paper, based on previous studies of the Donggou Copper Mine field we carried out investigation and laboratory research work which focusing on systematic sampling of the volcanic rocks, geochronology and isotope geochemistry of rocks, the formation of volcanic rock mining era and environment to study the mining of ore-bearing rock formation, deposit type, geological features, ore-controlling factors, to establish the metallogenic model, and exploration potential of the region. Main conclusions obtained as follows:1. Basic volcanic rocks of Donggou it has a mid-ocean ridge basalt (N-MORB) geochemical characteristics, that the deposit formed in an oceanic spreading ridge environment.2. Donggou mineralization in the ore-wall rock characteristics, ore bodies, ore type, ore mineral composition, rock alteration and so showed the "Cyprus-type" deposit characteristics, ore rock to ophiolite basic volcanic rocks in the upper part of that mine with the ophiolite the Cyprus-type deposits.3. U-Pb zircon geochronology indicates:the age of Donggou Copper ore volcanic rocks diagenetic is 499.8±2.0 Ma (MSWD=2.5), formed in the Late Cambrian; and copper produced in one of the Donggou is the role of volcanic seafloor hydrothermal convection caused by the role of the product cycle, mineralization also occurred in the late Cambrian. 4. Fluid inclusions showed that ore formation of inclusions in quartz are mainly gas-liquid two-phase inclusions, gas-liquid ratio is low; gas composition mainly CO2-based, liquid ingredients mainly H2O; forming fluid temperature 150～200℃, salinity 13～16%(NaCl), density of 0.87～0.95g/cm3.