Geological And Geochemical Characteristics And Genesis Of Vein Quartz Deposits In Luanchuan,Henan Province

Henan Luanchuan vein quartz deposits are located in the south of the middle section of Ma Chaoying in Henan Province Xiong'er mountain area.Tectonically,the deposits are located in the southern margin of North China platform.In this paper,three typical quartz vein deposits of M4,M11 and Shimenzhai were studied.According to field investigations,the characteristics of ore-controlling structure,orebodies occurrence and scale,mineral composition and wall rock alteration and so on of the vein quartz deposits were identified.Through indoor studies,the source,evolution and metallogenic environment of ore-forming fluids were discussed.Finally,the genetic types of the deposits were summarized.The main achievements are as follows:1.M4 and M11 vein quartz deposits are located in the porphyritic andesite Xushan Formation of Xiong'er Group.The Shimenzhai vein quartz deposit is located in the rhyolite porphyry of the Ji Danping Formation of Xiong'er Group.Orebodies are vein and lenticular.Orebodies' occurrence are strictly controlled by fault structures.Orebodies' trend are east-west.There is only silicification of wall rock alteration,other wall rock alteration is not obvious.2.According to the study of fluid inclusions,the ore-forming temperature is mainly concentrated in 100 ~ 160?,salinity is mainly concentrated in 6% ~ 8% Na Cleqv,the density was concentrated in 0.90 ~ 1.05 g/cm3.According to the uniform temperature-salinity calculation formula,the ore-forming depth is 1 ~ 2km,With an average of 1.38 km.The study indicated that the ore-forming fluids belong to the low-temperature,low-salinity and low-density fluids.3.The study of H-O isotope indicated that ore-forming fluids evolved from magmatic hydrothermal fluids and were driven by magma.During the process of migration,a large amount of precipitation was mixed,so that the precipitation in the fluid occupied the main component.4.The study of Si isotope indicated that ?30Si between quartz in research area and quartz in Nannihu,Luotuoshan metallic deposits are basically similar(0.1‰~0.5‰),which indicated that both cause type is the same.The Si isotope composition of quartz conforms to the hydrothermal genesis of-1.5 ‰ ~ 0.8 ‰.5.The contents and distribution characteristics of Trace and Rare Earth Elements between quartz in research area and quartz in Nannihu and Luotuoshan metallic deposits are basically similar.Standardized Spider Web of Trace Elements and Standardized Distribution Patterns of Rare Earth Elements indicated that the distribution trend is basically similar.Only the contents of Cu,Mo,W,Ba,Sr are different.It indicated that magmatic hydrothermal fluids between quartz in research area and quartz in Nannihu and Luotuoshan metallic deposits are similar,and may be the product of the same magmatic hydrothermal activity.