The Study On Metallogeny And Metallogenic Regularity Of Yingzuishan Gold Deposit In Northern Qilian Area,Gansu Province

Northern Qilian area, lying between Baoji in Shanxi Province and Subei County inGansu Province, locate in the junction belt of Northern China Plate and Chaidamu-QilianPlate. It’s an important tectonic metallogenic belt in China with a good ore-forming tectonicand geological background. Several Au, Fe-Cu and W deposits with different scales have beenfound in the studied area and Hanshan, Yingzuishan and Angzanggou gold deposits areattributed to the representative of shear zone type gold deposit by many researchers. On thebasis of previous research, the influence of structures on ore bodies have been analyzedcombining with detailed observation of geological and structural characteristics. Then,mineralizing periods are subdivided through petrography, mineralography and mineragenystudies. Finally, ore-controlling regularities are summarized on the studying of feature of faultstructures, rock bodies, strata and alternations. Results are as follows:(1) Yingzuishan gold deposit is developed in the intersection part of NE trending AltynFault and NWW trending regional fault, with ore bodies being obviously controlled by NWWtrending shear zones.(2) The host structures have typical characteristics of shearing zone. Furthermore, NWWtrending faults control the occurrences of ore bodies, whereas, NE and peri-NS trending faultsbreak ore bodies in different degrees.(3) Au mineralization, controlled by silicification and pyritization occurring in thecontact zone between volcanics and slates in Heicigou Formation, can be divided into twotypes, namely, silicalite and quartz-sulfide vein mineralization. The ore minerals are mainlypyrite and chalcopyrite, with minor galena, gangue minerals are mainly quartz, with littlecalcite, and wall rock alternations are dominated by silicification, pyritization andcarbonatization.(4) According our researches, mineralizing periods can be divided into magmatic,primary which can be subdivided into quartz-pyrite, quartz-pyrite-chalcopyrite-galena andquartz-calcite-talc mineralizing phases, and supergene mineralizing periods, in which primarymineralizing period is the main Au mineralizing period.(5) Minerageny testing results indicate mineralizing temperature220~280℃and lowexfoliation of ore bodies which is about35%in the third and fourth levels. Therefore, weconclude that the prospecting potential in the deep may be very well. (6) Yingzuishan gold deposit is localized in shear zones which are prior to Aumineralization and is related with orogenesis, so it’s attributed to orgaNic gold deposits.