Metallogenic Regularity Of Erdaogou Gold Deposit In Liaoning

Erdaogou gold deposit is located in the middle segment of north margin of North China Craton.Through nearly six months of fieldwork,downhole geological investigation,indoor analysis and comprehensive study,we identified the metallogenic geological setting,geological characteristics of Erdaogou gold deposit,geochemistry characteristics of ore-forming fluid,metallogenic material source and the metallogenic epoch,analysing the metallogenic regularity.The distribution of Erdaogou gold deposit is inhomogeneous.The thermoelectricity of pyrite is main P type and varies widely,with a small amount of N type,shoWing that the orebody erosion rate is low.The ?34S values of auriferous pyrite range from-3.6‰?1.1‰,and the average value is-0.91‰.The range is 4.7‰and small,demonstrating that the sulfur source is relatively single.The ?34S values fall near 0 with characteristics of magmatic sulfur.The 206Pb/204Pb,207Pb/204Pb and 208Pb/204Pb values of auriferous pyrite range from 17.101?17.217,15.363?15.407 and 37.189?37.356,respectively.They fall between the mantle lead curve and organic belt lead curve,near the latter,reflecting the source characteristics of the deep mantle and lower crust.The S and Pb isotopes of Xiduimiangou intrusive rock is consistent with that of Erdaogou gold deposit.Compared the trace elements of Xiduimiangou intrusive rock,volcanic rock at the mine with that of gold ores,we obtained that Erdaogou gold deposit and magmatic rock at the mine belong to the same chamber,the magma forming firstly and then ore-bearing fluid.The homogenization temperature in quartz fluid inclusion bearing gold ranges from 190?378 ?,most between 240?340 ?,and the average is 299.36 ?.The salinity concentration is 0-10(wt%)NaCl,with the obvious peak value 3.0?7.0wt%NaCl,and the average value is 5.1 wt%NaCl.The p of ore-forming fluid is 0.72g/cm3?0.805g/cm3.The estimated pressure ranges from 4.9MPa?12.8MPa and the metallogenic depth is 0.49km?1.28km,indicating that ore-forming fluid has medium-high temperature,low salinity and low density,and the mineralization depth is shallow.In conclusion,combined the temporal and spatial distribution of Erdaogou-Jinchanggouliang orebodies,the Erdaogou gold deposit is magmatic hydrothermal type,related to Xiduimiangou intrusive rock.