Application Of Short Wavelength Infrared(SWIR) Technique And Geochemical Prospecting Indications In Exploration Of Duo Baoshan Porphyry Cu Deposit In Heilongjiang Province,China

Duobaoshan copper deposit is the large-scale porphyry copper(gold)deposit in northeast China.With previous data collection and collation,field investigation sampling,experiments and analysis about the no.3 orebody of this deposit by short wavelength Infrared technique,the author studys the alteration minerals systematicly,combining the statistical analysis of elements geochemical characteristics of orebody.The main conclusions are as follows:(1)The analysis of SWIR alteration mineral testing shows that,the mine area's major alteration minerals(relative percentage greater than 5%)are illite,sericite(muscovite),epidote,chlorite(including sheridanite,daphnite);the secondary alteration minerals(relative percentage less than 5%)are montmorillonite,kaolinite,calcite,malachite,quartz,gypsum etc.According to thin section identification and XRD phase analysis,SWIR measurements of the main alteration through artificial recognition is well verified.(2)The mining area is divided into three alteration belts on the basis of alteration mineral assembly in the mining area: illite-epidote-chloritization belts,montmorillonite-illite-epidotization belt,kaolinite-sericitization belt.Moreover,montmorillonite-illite-epidotization belt show closely connection with copper mineralization,illite-epidote-chloritization belts locate the outside of mineralization zone.Kaolinite-sericitization belt is near the center alteration zone.(3)The wavelength position of Al-OH absorption and Illite crystallinities at Duo Baoshan can effectively reflect the copper mineralization.In spatial distuibution,the alteration mineral from mineralized segment has bigger Al-OH absorption peak position(greater than 2210~2215nm)and higher Illite crystallinities(greater than 2.0),both which are compared with rocks from no mineralized segment.According to Al-OH absorption peak position changes between the outside of mineralization zone and the center alteration zone,this phenomenon indirect show the temperature of mineralization might be between potassic alteration's and propylitization's,which is consistent with traditional opinion.SWIR technique has a good application prospect in mineral exploration of this deposit type and provides guiding suggestions.(4)Rocks elements,such as Cu,Bi,Au,Mo,in the montmorillonite-illite-epidotization belt of mining area show enrichment(enrichment coefficent>20),the character of Bi enrichment has priority in the outer orebody zone.The statistic analysis of elements find that the copper ore-forming interrelated elements are Bi-Mo-Au-Cd-K-Na.This elements group can be indicator for the orebody geochemical prospecting.Combining the application of SWIR technique and analysis of orebody geochemical characteristics,we find two kinds of exploration prospecting marks,which has been well verified in Duo Baoshan copper deposit's no.3 ore-body.