Coupled study of alteration system and spectral-geochemical characteristics of granite-pegmatitic type rare metal deposits,associated with Daqianggou mining area in western Sichuan Province
This article uses shortwave thermal infrared spectroscopy combined measurement technology and mineral geochemical analysis methods to study the coupling between the alteration system of granite pegmatite type rare metal deposits and mineral spectral geochemical characteristics,using 13 drill core samples from the Daqianggou granite pegmatite type Li-Be rare metal deposit in western Sichuan as the research object.The results indicate that:(1)The characteristics of the alteration zoning in the study area are(shallow to deep):muscovite→muscovite+albite→muscovite+hornblende+biotite+other plagioclase,with Li and Be ore bodies occurring in the muscovite+albite alteration zone.(2)The geochemical calculation results of muscovite minerals show that the short wave muscovite in the study area(wavelength less than 2200nm)has a formation pressure between 0.03GPa and 0.25GPa,with a formation depth of 1.3km to 9.6km,and a related mineralization type of Li and Be;The formation pressure of muscovite with wavelengths ranging from 2200nm to 2206nm ranges from 0.16GPa to 0.38GPa,and the depth ranges from 6.1km to 14.5km.The related mineralization type is Be;The formation pressure of long-wave muscovite(wavelength greater than 2206nm)is 0.45GPa,and the formation depth is 17.1km,without mineralization.Therefore,it is believed that the mineralization environment in the study area is between 200℃ and 500℃,with pressure values between 0.03GPa and 0.25GPa,and mineralization depths between 1.3km and 14.5km.(3)The wavelength of muscovite related to Li mineralization is less than 2200nm,and the displacement is within the fluctuation range of 10nm,indicating that the Li deposit may have formed during the magma hydrothermal mixing period;The maximum wavelength of muscovite related to Be mineralization is close to 2210nm,and the displacement has a fluctuation range of 20nm,indicating that the formation of Be ore is closer to the parent rock and can be formed from the late stage of magmatism to the magma hydrothermal mixing stage.(4)The application of GF-5 B hyperspectral remote sensing images to map different types of pegmatite shows great potential for mineral exploration in the northern periphery of the study area,with the Qiaopengzi rock mass as the ore-forming parent rock in the Daqianggou mining area.In this paper,the spectral characteristics of different types of pegmatites are determined by short-wave-thermal infrared combined measurement technology,and the important signs of remote sensing information identification of pegmatite-type rare metal minerals are determined by geochemical information.
Western SichuanInfrared spectroscopyPegmatiteAltered mineralsLi-Be mineralization
万方数据
维普
