The Alteration Characteristics And Prospecting Of Gangcha-Kemo Gold Deposit In Hezuo, Gansu Province

The Gangcha-Kemo gold deposit is located in Xiahe-Hezuo region,the northern margin of the West Qinling Orogen.This deposit is an epithermal one as shallow part of a porphyry system.This passage researches the alteration features of the Gangcha-Kemo gold deposit by short-wave infrared spectrum mineral analysis technique,and extracts,collects and analyzes the mineralizing information of geology,geophysics,geochemistry and alteration in mining area based on GIS platform,thereby offering evidence for further prospecting exploration.It has indicated that the developed alteration mineral in the region mainly contains muscovite,illite,montmorillonite,kaolinite,dickite,chlorite,epidote and quartz etc.Besides,there is also a small quantity of dolomite,calcite,talc,gypsum and so on.It is considered that according to spatial distribution and content variation trend of alteration minerals,phyllic alteration zone is mainly due to adjacent orebody alteration,which includes the combination of muscovite,illite and quartz.The characteristics of surface alteration mineral association indicates that central zone(phyllic zone),transitional zone(muddy zone)and peripheral zone(prophylitic zone)are developed from the bottom end of Xiajiamen Ravine as center outwards,which includes the combination of muscovite,illite and quartz;kaolinite,motmorillonite and dickite;chlorite and epidote.This zoning characteristics provides evidence about alteration for existence of porphyry metallogenic system in the Gangcha-Kemo gold field.The research of illite crystallinity indicates that the argument of the SWIR-IC value of surface illite crystallinity has showed obvious decreasing trend from the bottom end of Xiajiamen Ravine as center outwards,which demonstrates that the illite crystallinity is higer in the bottom end of Xiajiamen Ravine and constantly lowers outwards.This illite features indicates that the bottom end of Xiajiamen Ravine might be hydrothemal activity center of ore district.It shows from extracting,collecting the 12 pieces of favorable mineralizing information of geology,geophysics,geochemistry and alteration in mining area based on GIS platform that,there are much mineralizing favorable information on the bottom end of Xiajiamen Ravine including many faults,geochemistry element anomalies,polarizability anomalies,phyllic alteration,which is the most potential mineralizing area in the Gangcha-Kemo gold field.The above research results show that the crossing of Xiajiamen gully in the Gangcha-Kemo gold field is with great mineralizing potential.