THE GEOLOGICAL-GEOCHEMICAL CHARACTERISTICS AND GENESIS OF THE XIAOSHIMEN SILVER-GOLD DEPOSIT,HEBEI PROVINCE

The Xiaoshimen silver-gold deposit is a deposit newly discovered which located in southwest of the Xiaosigou porphyry copper-molybdenum deposit.The ore body is in vein or lens.The silver-gold mineralizations are mainly controlled by NNE faults,and connected with the Xiaosigou magamatic body and ivernite.Mineral assemblage is mainly medium-low-temperature mineral.The ore-forming temperatures are in the range of 240-365℃.Fluid inclusion studies indicate that the ore-forming fluid is rich in sulfur,and has higher K+,NH+4,Ca2+,Na+ content.The ore-forming fluid is mainly composed of magmatic water.Sulfur isotopic results indicate that sulfur of the deposit come from the magmatic system.REE investigations also show that the ore-forming materials originate from ivernite and the Xiaosigou magamatic body,and lead-zinc ore maybe partly come from the stratum.According to these data,the Xiaoshimen silver-gold deposit can be deduced to be a medium-low-temperature hydrothermal deposit.