Geological Characteristic And Oringin Of Mo Deposit In Huojihe Heilongjiang Province

The HuoJiHe Mo deposit is located in the north of XiaoXingAnLing-ZhangGuangCaiLing metallogenic belt, which is discovered nearby years as a good-sized one.Indicating with field-lab integration research, The mineralizing of HuoJiHe Mo deposit is focused on the Yanshanian biotite monzonitic granite,which putting up local mineralizing in this rock.The ore veins are controled of hydrothermal altered rock belt,and molybdenum ores major in the mineralized biotite- K-feldspar - quartz belt, granite- quartz network belt or sulfid joint vein belt.Showing the results of petrochemistry, microelement geochemistry and REE geochemistry research, the biotite monzonitic granite is the melting production of thickening the lower rock of crust ,which is related to mineralizing, have near affinity with adakites,and the same to the characteristic of high potass。So mantle-resource melts offer the ore-forming element in the original magma,just as Mo element。Indicating with fluid inclusion research,the mineralized fluid is belong to NaCl-H2O system。In the front of mineralization,the fluid has high-temperature and high-salinity characteres,and stand by the events of forepart magma evolvement.In metallogenic epoch,the fluid is style of medium-lower temperature and medium-lower salinity.The primary homogenization temperature of mineralized fluid of this deposit focus on the zone between 185.3 to 360℃,and the peak value is between 245.3 to 360℃.Based on the homogenization temperature and salinity of fluid inclusion,we can see that the fluid density is between 0.66 g/cm3 to 0.87 g/cm3, the mineralized pressure is between 38Mp to 85Mp,compared with the mineralized depth is between 4.9Km to 7.5km。In the zone of homogenization temperature,there are two different fluids of medium salinity style and lower salinity style,and it indicated the mixing action occurring at fluid evolvement in a certain extent。Indicating with the results of fine chronology research, the forming era of biotite monzonitic granite is 184.92±0.91Ma, which is related to mineralizing.So the granite is near related to the Mesozoic Yanshanian strcture-magma movement ,compared to early-Paleozoic Caledonian, which is considered by father workers. With the colligated researches, the form of HuoJiHe Mo deposit is related to the XiaoXingAnLing-ZhangGuangCaiLing orogeny in Mesozoic.When the movement makes the lithosphere thick, the magma usually comes of neonatal thick lower crust, remaining garnet and hornblende, finally forms as adakitic magma。And then with the extending circumstance,which is worked by subduction of Pacific Plate,the magmas intrude into the 4.9-7.5Km zone and finally deposit ores,and then form the low-F porphyry-vein style Mo deposit,which absent ore fluorite.