Studies On The Geochemical And Geological Characteristics Of Weiningbeishan Jingchangzi Gold Deposit

The Weiningbeishan Jingchangzi small-scale gold deposit is the most typical and largest gold deposit in Ningxia,which is located in the east North Qilian orogenic belt of Qinling-Qilian-Kunlun orogenic system, north to North China Alxa area, east to North China Ordos area, appertaining the superimposed parts of tectonic activity and stability plots, and only exposing upper Devonian Laojunshan groups, former lower Carboniferous Montenegro groups, Chouniugou groups, upper Carboniferous slopes groups and a small group of Holocene aeolian sand, red diluvium. The research area is characterized by developmental EW folds, faults and north-east, south-east of conjugate shear zone, that the principal compressive stress is north-south. Magmatic activity in the region is weak, there being a little diorite dykes and brite veins, quartz veins and calcite veins.In this paper, we have synthetically used the integrated basic geological data, analysed the geological background, applied the petrology, tectonics, geochemistry of mineral deposits, studyed the geochemical and geological characteristics, deposit genesis systematically, made sure the type of deposit genesis and set up metallogenic models in order to provide theoretical guidance for future work.The Jingchangzi gold deposit has small scale and low grade with a east-west overall structure.The systematic study of the near mine rock, magmatic rocks, trace elements in the ore, REE and isotope has demonstrated that ore-forming elements Au came from the stratum of upper Devonian Laojunshan groups and former lower Carboniferous Montenegro groups. Primary ore and oxide ore accounted for the major part, that wall-rock alteration appear commonly as pyritization, limonitization, Jarosite, siliconization etc.. On the research of the quartz inclusions and the isotope of H,O, Ore-forming fluids which were mixed by precipitation and interlayer water, finally turned into the mineralizing fluid by tectonization had the characteristics of mid-low temperature, high salinity, in which late mineralization a small amount of magmatic hydrothermal joined.The main ore-forming elements are that:1. Gold-bearing sedimentary-What there being Au in the upper Devonian Laojunshan groups and former lower Carboniferous Montenegro groups formed the source bed.2. Structure-The EW fracture, fold and structural fracture zone provided space for lead ore and ore hosting.3. Ore-forming hydrothermal-Mixture of precipitation and interlayer water turned into the mineralizing fluid by tectonization and where a small amount of magmatic hydrothermal joined.4. Mineralization age-SHRIMP Test Results of Zircon showed that Diorite in the deposit had two periods of magmatic activity:170Ma and143Ma-148Ma. The later period of the mineralization was later than or close to143Ma.In conclusions, The Jingchangzi gold deposits are sedimentary, which have been further enriched after being constructed by hydrothermal. The study has determined the gold deposits to be sedimentary rocks associated fine disseminated (Similar to Carlin type gold), Research on the causes of the gold deposits and the Metallogenic model can provide guidelines for finding the similar type of gold deposit in Ningxia.