| There is a big dispute of the genesis of mineral deposit about Zhaxikang,whicn is the best Pb-Zn deposit in the Himalayan metallogenic belt.On the basis of the previous research,detailed field works,indoor ore microscopy study,fluid inclusions study,S-Pb isotopic analysis,artificial earthquake detection experiments,characteristics of regional geochemical,source and migration patterns of ore-forming material,metallogenic characteristics,and zoning model had been discussed.In the end,the prediction of mineral has been done by collecting geological,geophysical and geochemical information.Some conclusions were made:The ore bodies of Zhaxikang lead-zinc deposits mainly occurred in high angle normal faults in the SN direction,and the dip angle is 50-60°.They are strictly controlled by the faults,without bedding ore body.The galena and sphalerite in the deep ore deposits is lump and brecciated,which are the highest degree of crystallization and the largest particles,and they are cemented by ferromanganese carbonate.The arsenopyrite ? Pb-Sb sulfosalt mineral and quartz appeared in turn from deep to shallow.The range of wall rock alteration is very small,and there are no typical high temperature alteration minerals.This phenomenon might be the results of multistage superposition process.Fluid inclusion studies about sphalerite and quartz show that the ore-forming fluids is medium temperature?medium-low salinity?medium-low density,with the temperature(200-293?),the salinity(2-16%),the density(0.75-0.95 g/cm3).The temperature and salinity of quartz fluid inclusion are lower than the sphalerite fluid inclusion.The result of ?18OH2O-?18DV-SMOW and the Chromatographic analysis prove that the late ore-forming fluids are from geothermal water.But the composition of the early ore-forming fluid is closed to the fluid in the deep stratum.The sulfur isotope variation of Zhaxikang ranges between 4.5 ‰ 13.2 ‰,which is different from Magmatic hydrothermal type deposit.The lead isotope results is closed to the radioactive lead and the ? value has the characteristics of the crustal material.The sulfur and lead isotope results of the Zhaxikang indicate the ore-formingmaterial source is from the earth crust.According to the results of the comparison of deposit-district geochemical characteristics,including the J1 r,the TriassicCretaceous stratum and the diabase in the eastern section of tethys Himalaya could provide lead and zinc ore-forming material.Through the interpretation of 2D time migration section,a number of deep faults were found in the ore district,but there are no obvious reflected wave signals by intrusive rock.The formation of deep fracture is related to the transformation of India-Asia plate collision-stretching structure,which provided the channel for oreforming fluid to extract and transport Pb-Zn from the stratum.The intersection location of the faults is the advantageous position for the ore-forming and hydrothermal overlapping and reworking.Therefore the Zhaxikang early lead-zinc deposits are medium-low temperature hydrothermal filling ore deposit,which were formed in the Indian plate colliding to Eurasian plate in Miocene post-collisional transition environment.These deposits have been overlapped and reworked by the hydrothermal.On the basis of the Zhaxikang type lead-zinc metallogenic model,this paper collected the diverse information about geological,geophysical and geochemical.It is a successful attempt to infer the modeling of main ore-controlling faulted structure in the zhaxikang lead-zinc deposit by using the technology of data fusion of geologicalAMT and artificial earthquake.Combined with the superposition primary halos of the existing research results,in this paper,the research about the deep ore and periphery of concealed ore prediction has been completed. |
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