| Tuanjiegou gold deposit is located in wulaga town,Jiayin county,Heilongjiang province.It is in the east of wulaga basin,verge of Hegang border uplift and fault. The deep NNE trend fault devide the wulaga.Rift of Hegang and basin into two part.The strata exposed in the region mainly include Proterozoic and Cenozoic.Intrusive rocks are exposed extensively and complexly.Intrusive rocks consists of acid intrusive rocks of Proterozoic, ultramafic rocks of Paleozoic, granitic intrusive rocks of Late Triassic, Late Triassic - Early Jurassic and early Cretaceous From old to new,the intrusion age are Luliang,Jinningian, Indo-China and Yanshanian periodRegional volcanism is well developed.They are mainly exposed in wulaga town - Willow River sub-area of the east of Wulaga basin,while a small amount of them exposed in Shangmaqihe on the west side of the basin.It can be divided into two periods: Ningyuan Village period and Fumin River period.Folds and faults are development in the region. Fold in Proterozoic metamorphic rocks formed for the deformed Maljan station, the center channel complex anticline and syncline between the complex, were en echelon arrangement, the overall inclined to back the North East - Southwest. Faults can be divided according to NNE, from east to west, north and south to breakage.Tuanjiegou gold deposit has explored more than 80 ore bodies.and 6 main ore bodies. They are controlled by breccia belt in plagioclase granitic porphyry,and they are mainly distributed in it.Only a small number of them are associated with scattered and fragmented pieces lean ore rock between the fracture zones, alteration zones.Primary types of gold ore include colloidal chalcedonic quartz - pyrite, carbonate - pyrite, gold jelly - chalcedony-like quartz - stibnite type and rich sulfide. Secondary ore is limonite type,and this type is contained in the oxidized zone. Ore minerals include are gold, pyrite, small amounts of stibnite, silver, sphalerite, mercury, galena, chalcopyrite, realgar, orpiment and jarosite. The secondary mineral is brown iron.Gangue minerals include chalcedony quartz, micro granular quartz ,comb quartz, calcite, colloidal opal, dolomite, feldspar, quartz, kaolin,and so on.There are many types of ore structures, mainly include colloidal structure, mosaic structure, fine granular structure, fine crystalline structure,inclusion structure and droplet-like structure.The development of low temperature structure is an important feature of unity GOLD one.Ore textures mainly include vein, stockwork texture,and most developed brecciated texture, in addition to developing a disseminated texture, gel-like and crystal and other hole textures.Complex wall-rock alteration apperes in the area, mainly pyrite phyllic, ice Petro-Chemical, silicification, carbonate, clay and so on.Silicification is most closely with mineralization.The temperature of fluid inclusions ranges from 150℃to 280℃. The main value is between 150℃and 220℃. The salinity ranges from 1.39~5.99 wt%NaCl, with the average 3.4wt%NaCl. The main salinity is between 3.0~4.1wt%NaCl. The value of density is between 0.78 and 0.93g/ cm3. The value of pressure ranges from 10.2~14.1MPa.Thus determine that Tuanjiegou gold deposit has characteristics of low salinity , low temperature and low density. According to the Characteristics of laser Raman and Isotopic liquid. Major components of mineralizing fluid is water; S isotope studies show that Mineralization from granite; Pb isotope studies show Tuanjiegou magmatic plagioclase granite plaque not only provides the mineralizing fluid, also provided some of the forming materials.Study on major elements shows the intrusive rocks of this area are all calc-alkaline granitic porphyry, while the volcanic lava and pyroclastic rocks are also shown the nature of calc-alkaline igneous rocks.The characteristics of the rare earth and trace elements suggest that the volcanic rocks and igneous rocks are the product of Comagmatic Evolution.The zircons from granodiorite-porphyry give U-Pb ages of 119-100Ma, with a weighted mean value of 109.7±3.8Ma, shows that is the production of early Cretaceous magmatism. Its formation is closely related to the subduction of the Mesozoic Pacific plate towards the Asian continent, this caused the formation of acid magma, and intruded upward along NNE-NE deep faults passively, this belong to production of fault expansion or calderas in passive mechanism. The age of single grain zircon from dacite cuttings crystal tuff is 121-102Ma, with a weighted mean value of 108±2Ma. On the formation environment discrimination diagrams, the composition points of typical volcanic fall under the area of continental margin, this feature reflects the volcanic rocks of Ningyuan village period formed at continental margin environment.Late Mesozoic Early Cretaceous, the subduction of the Mesozoic Pacific plate towards the Asian plate formed the NNE-NE trending Wulaga deep fault. Under the continental margin environment, series of calc-alkaline volcanic lava and pyroclastic rocks magma, which was caused by partial melting of the basement, migrated upward along Wulaga deep fault, and emitted surface, as the pressure in magma chamber reduced continuously, the magma was unable to erupt to the surface, and crystallized rapidly in shallow crust, thus formed the shallow plagioclase-granite porphyry, granodiorite porphyry and granite porphyry intrusions, which output as stocks. The sub-volcanic hydrothermal caused by differentiation in magma chamber migrated upward along Wulaga deep fault, while extracted the minerals of plagioclase granite porphyry, granodiorite porphyry, granite-porphyry intrusions and the old base rocks, was gradually enriched to form the ore-bearing hydrothermal, meanwhile mixed meteoric water. The formation of the gold deposit underwent mainly two main stage: one stage is brecciated gold mineralization period, which outputs in the tectonic breccia zone. Another stage is the vein, stockwork gold mineralization, the enrichment and precipitation happen at the NW-NWW trending secondary fault of the NNE-NE trending Wulaga deep fault.Thus form this typical low sulphidation epithermal gold deposit.
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