Metallogenic Regularities And Metallogenic Prognosis Of Gold Deposits In Xinlin-Han Jia Yuan Area,Great Xing'an Range,China

The Xinlin-Han Jia Yuan area is located in the eastern slope of Northern Great Xing'an Range.The geotectonic belongs to eastern of Central Asian Orogenic Belt,neighboring the Siberian Plate in the north and the ancient North China Craton in the south,which is an important area full of gold,iron,alum and titanium polymetallic ore concentration area in Great Xing'an Range.The genetic types of gold deposits in Xinlin-Han Jia Yuan area of Great Xing'an Range are mainly of medium-low temperature hydrothermal vein type.The representative deposits are Walali gold deposit,Heilonggou gold deposit and Fenghuangshan gold deposit.The metallogenic characteristics of the Walali gold deposit are similar to Heilonggou gold deposit.The mineralizing surrounding rocks are metamorphic rocks of Neoproterozoic Xinghuadukou Group and Late Carboniferous granite.The results of petrogeochemical study show that the Late Carboniferous granite formed subduction of Paleo-Pacific oceanic plate,and the magma were sourced from the crust.The study of inclusions of ore-forming fluids shows that the fluid in the early stage of mineralization originates from magmatic water,atmospheric precipitation participates in the fluid of metallogenic epoch,and the main fluid of late metallogenic epoch is atmospheric precipitation.H-O isotope studies show that the values of?D and?¹⁸O_H2O2O obtained from quartz samples fall within the fields of magmatic water,which reflect that the ore-forming fluids for were derived from magmatic water.The results of S-Pb isotope of ores show that the value of?³⁴S_?SS from 7.2 to 13.3,the range of variation is small,and the sulfur of ore-forming materials is from a single source,mainly from the crust.The lead isotope composition has crustal characteristics.The migration and enrichment of lead in ores are related to the influence of the closure of the Mongolian Okhotsk Ocean,and the lead mainly comes from the crust.The mineralizing surrounding rocks of Fenghuangshan gold deposit are metamorphic rocks of Neoproterozoic Xinghuadukou Group.The results of petrogeochemical study show that the Neoproterozoic Xinghuadukou Group formed an extensional environment related to the breakup of the Rodinia supercontinent,and the magma were sourced from the mantle.The study of fluid inclusions shows that the ore-forming fluid is high salinity and medium-high temperature H₂O-NaCl system hydrothermal fluid,and NaCl-bearing three-phase,gas-rich and gas-liquid two-phase fluid inclusions are developed in stage II;the ore-forming fluid is medium-low salinity and medium temperature H₂O-NaCl system hydrothermal fluid,and the gas-rich and gas-liquid two-phase fluid inclusions are developed in stage III;the ore-forming fluid is low salinity and medium-low temperature H₂O-NaCl system hydrothermal fluid in stage IV.The H and O isotope studies of the Fenghuangshan gold deposit show that the value of?¹⁸O_H2O-SMOW ranges from 5.4 to 6.2,fall within the fields of magmatic water,which reflect that the ore-forming fluids for were derived from magmatic water and mixed with some atmospheric precipitation,and the participation of atmospheric precipitation in late ore-forming fluids becomes greater.The results of S and Pb isotopic show that the sulfur and lead isotopic compositions of ores have mantle characteristics,and the migration and enrichment of lead in ores are related to the influence of the closure of the Mongolian Okhotsk Ocean.Rb-Sr isotopic dating and Zircon U-Pb dating show that mineralization in Xinlin-Han Jia Yuan area of Great Xing'an Range is Early Cretaceous mineralization.The ore-bearing rock-bodies of Fenghuangshan gold deposit,Walali gold deposit and Heilonggou gold deposit are intermediate-acid vein rocks.Many vein-type deposits are developed in Xinlin-Han Jia Yuan area of Great Xing'an Range.The development and distribution of gold deposits in study area are mainly controlled by structure and stratigraphic magmatic rocks.According the MRAS system,we dicover that important prospecting marks are Neoproterozoic Xinghuadukou Group,Paleozoic Niqiuhe Formation and Tongshan Formation,Variscan and late Yanshanian magmatite.Compared the geochemical and geophysical data of study area with known mines,and the anomalies favorable for mineralization are selected.Finally,we extracted Neoproterozoic Xinghuadukou Group,Paleozoic Niqiuhe Formation and Tongshan Formation,Variscan and late Yanshanian magmatite,tectonic isodense anomalies,entropy of stratum assemblage,geophysical anomalies,geochemical etc.as evidence,using MRAS system,and marked out 7 prospecting target areas.