Study On Geological Features,Geochronology And Isotope Geochemistry Of Luyuangou Fractured Altered Gold Deposit,Western Henan Province

Luyuangou fractured altered rock-type gold deposit in Xiong'ershan area of western Henan Province is located on the interlayer slip fault,which is the representative of the extensional tectonic ore-controlling and is a rare example of study on splitting mineralizing of the southern margin of the North China Craton.In this paper,the geological features,ore-controlling factors,material source and metallogenic mechanism of the deposit are discussed through the mineral deposits,mineralogy,geochronology and isotope geochemical analysis.The achievements obtained as follows:1.Luyuangou gold deposit belongs to the thin layer fractured alteration rock type ore deposit controlled by interbedded tectonics,and the mineralization process is closely related to the metamorphic core structure of the metamorphic core complex caused by the Mesozoic late north-eastward extension system.2.The mineralization of the deposit can be divided into two mineralization episodes containing four mineralization stages.The first episode is the deepening period of the first uplift of the metamorphic core complex,which is divided into two stages:(1)quartz-pyrite-gold mineralization stage;(2)quartz-polymetallic sulfide stage.The second episode is that the superficial mineralization period of the tectonic magma caused by the second uplift of the metamorphic core complex can also be divided into two stages:(1)quartz-lead silver mineralization stage;(2)carbonate-fluorite-natural silver gold mineralization stage.The gold minerals in the Luyuangou gold deposit are mainly in the form of independent minerals in quartz,pyrite,chalcopyrite,sphalerite,galena and other minerals.The occurrence form of gold is dominated by microscopic gold.The relationship between the occurrence form and content of gold illustrates the gold has a multi-stage,multi-type mineralization characteristics.3.The weighted average age of zircon U-Pb in the Luyuangou gold deposit is 450±13Ma,which represents the zircons captured from the deep ore through the mineralization structure.The zircon U-Pb age of the quartz monzonitic porphyry veins is 121.1±1.5 Ma,which represents the Yanshanian tectonic event,and Yanshanian may be the main metallogenic period of the Luyuagou gold deposit.4.The ?Nd(t)and ?Hf(t)of the masanophyre dyke from Luyangou gold deposit show that is consistent with the trend of crustal evolution in the Qinling Group.The age of the zircon Hf model of the ore vein and masanophyre dyke,and the Nd model ages of the veins are between 1.4Ga and 1.7Ga,which shows the kinship of Qinling Group in North Qinling.The S-Pb isotopes of pyrite in gold ore show the mixture of Qinling group and ore-forming material from deep faults.5.The comprehensive study shows that the crustal depression and crustal thinning are further induced by the subduction of the Pacific plate in the southern margin of the North China craton,and the corresponding superficial events are metamorphic core uplift and medium-acid magmatic activities.Accompanied by the extensive mineralization activities,the formation of Luyangou gold deposit is located in the inter-layer slip detachment fault zone.