Alteration Mineral Feature Of Drill Cores From Xiangshan-zoujiashan Extracted By Hyperspectral Remote Sensing Technology And Geological Significance

Hyperspectral remote sensing technique can be applied to rapidly mineral identification and dividing altered belt and estimating mineralization/hydrothermal center.It can be applied in Xiangshan uranium oral-field and the altered mineral here need further studied.This study was based on hyperspectral remote sensing technique and we used the hyperspectral data of 3 drill cores from Zoujiashan to extract altered minerals and catalog it.The study shows the following conclusion:(1)We mainly extracted poor aluminum illite,rich aluminum illite,chlorite,smectite,carbonate,dickite and kaolinite.The main absorption band of dickite and kaolinite is around 2210 nm.The Al-OH absorption wavelength of poor aluminum illite is around 2223 nm while rich aluminum illite is 2210 nm.The main absorption band of chlorite is around 2367 nm and 2265 nm,presenting characteristics of ripidolite which reflected the reductive environment of hydrothermal.(2)These altered minerals showed the vertical feature that the upper is acidic and lower is alkaline and acidic-alkaline superposition.The upper drill core content more rich aluminum illite,while the lower content less,which shows the distribution characteristics of acidic altered minerals,and the content of poor aluminum illite is less in upper core but more in lower core.Carbonate is widely spread and mainly founded in dyke.The spread forms of these altered minerals show that structure influenced the migration of the fluid.Mineralization area presented an assemblage of poor/rich illite,chlorite,carbonate and hematite.(3)When contrast 3 drill cores and geological data we found that alteration is much stronger in structural fracture zone or cracks while ZKR1 drill hole whose structure and lithology are more homogeneous has a less changing in alteration.ZK2 drill core shows that damouritization,chloritization,hematitization and dense fracture are closely related to uranium mineralization.During the long-term of activity,the deep-source alkaline fluid gradually turned into neutral and acid,then overlaid and reformed the alkaline hydrothermal alteration which may cause the result of this alteration laws.This study used “hourglass” procedure to extract spectral of illite and contrasted 3 drill cores.It presented that the illite crystallinity(IC)value of Short Wavelength InfraRed(SWIR)and the wavelength of 2200 nm absorption increases with the depth.The primary factor of the illite 2200 nm absorption position maybe the ion concentration of different hyperspectral.How temperature influence the content of Al in clay minerals needs to be further studied.In general,this study got a good result by applied hyper-spectral imager to alteration extraction and core logging.We could get rich alteration information and more geological information.