GEOLOGICAL CHARACTERISTICS AND PREDICTING FOR BLIND OREBODIES OF DONGWAN GOLD DEPOSIT IN SONGXIAN, HENAN PROVINCE

The Dongwan gold deposit in Songxian, Henan Province is controlled by a structural alternation zone. The orebodies occur as veins or lenses, with ores in veinlets, disseminated, veins, stockworks and honeycomb-style. The ore minerals include natural gold, electrum and natural silver, with minor sulfates. The main alternations consist of silicification, sericitization, kaolinization, carbonation and pyritization. The mineralization is divided by four stages:silicification (pyritization) stage, quartz-coarse pyrite stage, quartz-fine pyrite stage and carbonate-galena-sphalerite stage. Based on the theory of structural overprinted geochemical halo, the model of structural overprinted geochemical halo for Dongwan gold deposit is constructed, by which blind orebodies are prospected successfully.