The Study Of The Ore Characteristics And Mineralization Epoch Study Of The Gaosongshan Gold Deposit In Heilongjiang Province

The Gaosongshan gold deposit is located at the intersection part ofWuyun-Jieyaxin depression belt in the Xiao Hinggan Mountains-Songnen block andWuxing-Guansongzhen central uplift in the Yichun-Yanshou folded belt. Strataoutcropped in the district are mainly Lower Cretaceous Banzifang Group, consistingof andesite, dacite, breccias, pyroclastic rocks and tuff, and Ningyuancun Grouprhyolite and rhyolitic tuff. Magmatic activities are intensive in the Gaosongshandeposit. Yanshanian dacite and andesite intruded into the volcanic clastic rocks, tuffand rhyolite as dykes. Orebodies are strictly constrained in the fracture zones,occurring as nearly E-W trending veins, with andesite and volcanic breccias as themost important host rocks.This paper focused on the ore characteristics studies, i.e. ore compositions,textures and structures, and divided ore-forming stages on the basis of mineralassemblages, alteration and crosscutting relationships of veins in the Gaosongshandeposit.1. Ores of the Gaosongshan gold deposit are predominantly veins or breccias,with mior dissemination mineralization in the alteration rocks. Ore minerals consistof native gold, pyrite, and occasionally chalcopyrite and galena. Gangue mineralsare quartz, chalcedony, calcite, chlorite, epidote, kaolinite, and rarely adularia.Alteration types include silicification, sericitization, kaolinization, chloritization,epidotization and carbonitization.2. Ore textures of the Gaosongshan gold deposit can be divided into crystaltexture and replacement texture. The crystal texture can be further classified intoseveral subtypes, i.e., panautomorphic, hypautomorphic and allotriomorphicgranular textures and poikilitic texture. The replacement textures includereplacement remnant texture, erosion texture, illusion texture and reaction rimtexture. Ore structures are stockwork, miarolitic, drusy, crustiform, lattice, foliated, brecciated, and comb structure.3. According to the geological characteristics, ore fabrics, mineral assemblages,alteration type and crosscutting relationships,combining to our microscopicexamination, we divided the mineralization process of the Gaosongshan gold depositinto hydrothermal and supergene period. The hydrothermal period can be furtherclassified into4stages, while the supergene period overlapped all the hydrothermalstages and formed oxidized minerals, like limonite.