Geochemical Characters Of Fluid Inclusions Of The Ore-body In The Magma Domal Structure And The Argument On The Genesis Of The Deposit In Jinchang Gold Deposit, Heilongjiang

As one of the currently large operational gold mines in China,Jinchang gold deposit in Heilongjiang is located geotectonically within Xingkaihu Block,which has regionally experienced intense structural and magmatic activities.Many scholars have done a lot of research since 60s of last century and it is concluded that despite of many agreement on most aspects of Jinchang,different opinions on the ore-forming origin,divisio.n on mineralization stages and genesis still exist.This paper starts with the geochemical features of the ore-forming fluid and tracks down the origins of ore-forming materials and ore-forming fluid as well as physical-chemical conditions and mechanism during mineralization,thus providingthe evidence for genesis of Jinchang gold deposit. A series of field work including sample collection along with a lot of indoor work such as microscope observation and testing for fluid inclusion as well as Raman spectral analysis were completed during the study for Jinchang gold deposit.It is concluded that ore-forming fluid inside the magma domal structure was formed in the epithermal-mesothermal environment in a relatively wide range of salinity reflecting boiling characterist- ics . Additional outcome indicates that the mineralization fluid was originated from the deep level although some meteoric water added in and diluted later at the high level.Finally,this paper draws out conclusions for Jinchang gold deposit:magmas is thought to be the origin for gold mineralization;enough crystallization and differentiation of magmas is the key to mineralization; abundant volatiles include water , C02 and CH4 are favorable conditions for mineralization in the region.In the end,it is suggested that porphyry type Cu(Au)should be put on the top when prospecting in magma domal structure.