Chronology And Metallogenic Material Source Of Dongliang Gold Deposit In Eastern Hebei

Dongliang gold deposit is located in the eastern Hebei Province,which is a medium-sized gold deposit in recent years.The gold deposit occurs in an ancientvolcanic structure in the form of thick veins.The genesis of the deposit remains to be determined.Therefore,based on the field geological survey,through the mineralogical observation,fluid inclusion test,Sims zircon U-Pb dating,molybdenite Re-Os dating,and C-H-O-S isotopic analysis,we have made the following main achievements and understandings on the ore-forming chronology,material source and mechanism ofDongliang gold deposit?1?According to the interpenetrating relationship of ore vein,parageneticAssociation of minerals and structural structure of ore,the metallogenic process of Dongliang gold deposit can be divided into molybdenum mineralization sub period and gold mineralization sub period.Among them,the metallogenic sub stage ofmolybdenum is divided into two metallogenic stages,i.e.potash feldspar stage and quartz molybdenite stage;the metallogenic sub stage of gold is divided into four stages,i.e.pyrite quartz stage,quartz pyrite stage,polymetallic sulfide stage and carbonate stage.?2?The SIMS zircon age of quartz monzonite porphyry is 162.3±1.3Ma,and the Re-Os isochron age of molybdenite is 164.5±2Ma.?3?The average value of?³⁴S is+1.49‰,?¹⁸O_H2O is between 0.5‰and 2.4‰,?Dv-smow is-70‰,?¹⁸O_H2O is between 6.2‰and 7.4‰,?Dv-smow is-80‰,and calcite?¹³C is between-1.1‰and 3.5‰,indicating that the ore-forming fluid ofDongliang gold mine is mainly rock slurry water mixed with atmospheric precipitation,and the ore-forming material comes from deep magma.?4?The formation of gold deposits in Eastern Hebei is related to the middle Late Jurassic paleovolcanic activity,which belongs to subvolcanic hydrothermal type.It was formed in the subduction tectonic setting of the ancient Pacific plate.