| The Qingshan gold deposit is located in the northern margin of Chaidamu,Tanjianshan Au,Cu,Mn,Fe metallogenic belt,which is rich in mineral resources and superior in metallogenic conditions.It is one of the important metallogenic belts in our province.Six structural altered rock type gold deposits,such as Jinlonggou large gold deposit and Qinglonggou medium gold deposit,have been found in this belt,which shows a great prospect for the exploration of gold deposits.This paper takes the gold deposits in Qingshan area as the research object.Through the analysis of the regional geological background and the geological characteristics of the deposits,the genesis of the deposits is determined and the prospecting marks are defined,which provides a basis for the next prospecting.The main control ore in the mining area is the NW-trending fault,with the characteristics of the"broom"-controlled structural style,the interlaminar fracture zone is the main ore-bearing fault,and the mineralization of the composite part in the"broom"structure is good,and the mineralization enrichment along the"broom"structure has the rule of transverse corresponding and sectional enrichment.The NW-trending fault in the ore-forming period is a feature of the tension,and the local variable and steep part of the vertical fault zone is the open part,and the mineralization is good.The metal minerals in the ore of Qingshan gold deposit are mainly pyrite,and the natural ore type is mainly the fractured zone alteration rock type.The lode minerals are mainly quartz,chlorite and calcite.The ore structure is mainly granular,cataclastic and metasomatic pseudomorph texture.The ore structures are mainly massive,veined,and disseminated structure.The wall rocks of the main ore are quartz schist and diorite-porphyrite.The Wall rock alterations include phyllic zone,chloritization,silicification and carbonatization.Lithology and silicification are closely related to the ore-forming space.There are 5 alteration zones and 23 orebodies in the area,of which 12 are gold and lead orebodies.Most of the orebodies are ribbon and lentoid.The length is 501640 m,the inclined depth is 20185 m,the true thickness is 0.8414.53 m,the average Au grade is 1.0×10-68.84×10-6,and the average Pb grade is 0.33×10-2.1.28×10-2.The temperature of the Qingshan gold deposit is 159.0240.7?,the average salinity is 197.6?,the salinity is 5.8511.48 wt%NaCl,the average salinity is 9.8%,and the fluid density is 0.900.98g/cm3.It is shown that the ore-forming fluid of Qingshan gold deposit is medium-low temperature,medium salinity and low-density fluid,and the estimated ore-forming depth is 1.562.60km.The deposit type is a shallow,medium and warm liquid vein type gold deposit.The Pb in the study area is abnormally high,and the gold and lead orebodies are mainly developed on the surface and shallow part of the vein,indicating that the denudation of the deposit is small and the preservation conditions are better.The gold ore body in the study area has a tendency to become richer in depth,the prospecting is based on structural mineralization and enrichment law?corresponding to the mineralization horizontally?,the trending northward and vertical upwards of occurrences steeper part;"broom"structure development area swiftly decimated to the southeast,the scale of the tectonic zone became larger in the northwest direction.The main tectonic zone should be attacked to go deep in the northwest direction. |
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