Study On The Enrichment Regularities Of Mineralization Of Tugurige Gold Deposit In Urad Zhongqi, Inner Mongolia

Tugurige gold deposit is situated in Urad Zhongqi, Inner Mongolia. Geotectoniclocation lies in the middle of Central Asian orogenic belt, which the north is bounded bySuolun-Linxi deep fault, and the south is bounded by Xilamulun deep fault. The study areawith the ancient North China plate base is belong to Bainaimiao-Wenduermiaoepicontinental accretional belt, which was controlled by paleo-asian ocean tectonicdomain in the Paleozoic.Most of the exposed strata in this area are the uppest subgroup of Lower ProterozoicBaoyintu Group and Quaternary. The uppest subgroup of Lower Proterozoic BaoyintuGroup contains light gray-gray quartzite, marble-grey garnet mica schist and quartz-micaschist. Magmatic rocks are widely distributed in diggings, According to the intrusion age,there are the Silurian granodiorite and albite granite, the Permian porphyraceousmonzonitic granite, hornblendite, amphibole gabbro and quartz diorite. The Permianporphyraceous monzonitic granite with adakites characteristics is formed in the Siberianplate and North China plate collision stage of partial melting of crust thickening. Quartzdiorite, which is formed in the backward from the collision between the two plates havereferred collision transformation of tectonic setting, provide main material source and the rising power for the migration of hydrothermal ore forming solution in this area. The mainstructure of the west diggings is NW fracture structure, which should be the secondaryfracture of fault on the area. The main structure of the east diggings is NE fracturestructure. Orebody are filled in the fracture structure by quartz vein.The main type gold mineralization in the diggings is lode, containing structure alteredrock type. Quartz vein orebody mainly include the7,2,2-1,2-2,2-3,33,18,125lode inwest diggings and the8lode in east diggings. The length of each lode is between600～1600m, and the width is between0.8～2.0m. These ore veins become thicker when theirorientation changed in horizontal direction and their inclination have been flatter. Eachlode in west diggings has the regular of lateral trending to NW, and the8lode in eastdiggings has the regular of lateral trending to NE.Metallic minerals in Tugurige gold deposits are mainly pyrite, chalcopyrite, galena,sphalerite and a little limonite and covellite. Gangue mineral are mainly quartz, calcite,anorthose, chlorite and so on. Major textures of ores are euhedral-subhedral granulartexture, poikilitic texture, solid solution exsolution texture, replacement ring edge texture,cataclastic texture. The major structure is disseminated structure. The country rockalterations are mainly silicatization, sericite-quartz alteration, chloritization, epidotization,potash feldspathization and carbonatation. Silicatization and sericite-quartz alteration areclosely related to the mineralization. The mineralization period can be divided into threephases: quartz-low sulphide mineralization stage, quartz-sulphide mineralization stage,quartz-carbonate formation stage.Quartz fluid inclusion of Tugurige gold deposits demonstrate that the homogenizationtemperatures of mineralization are200～260℃, the scope of fluid salinity is6～14%NaCl,density of0.84～0.90g/cm3, the pressure of mineralization is66～104MPa, the depth ofmineralization is5.5~7.5km, in the main mineralization stage. Raman analysis of fluidcomposition, the gas phase composition of the ore-forming fluids mainly H2O, followedfor CO2. The result show that it is a H2O-NaCl-CO2system.The34SV-CDTvalue of pyrite from Tugurige gold deposit changes in the range of -9.0‰～-0.5‰, and the δ34S value changes in small range, with obvious tower styledistribution, which shows that the metallogenic material derived from the LowerProterozoic Baoyintu Group and magmatism before the mineralization. The δ18OH2Ovalue of quartz suggest that the main sources of ore-forming fluid is magmatic water, witha little of atmospheric water and surface water in the late.According to the tectonic background, geological characteristics and the mineralizingcondition of Tugurige gold deposits, we conclude that the deposits could be classified asmesozonal orogenic gold deposits, proposed by Groves（1998）.