Lithology Identification of the North Qilian Belt by Surface Temperature and Spectral Emissivity Information Derived from ASTER TIR Data

Abstract

Lithology units have been identified in northern Qilian belt by using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) thermal infrared (TIR)L1B data which contains both surface temperature and spectral emissivity information. As mafic-to-untramafic units have higher surface temperature than other geologic units, surface temperature images were generated to identify the dolerite and peridotite etc. Reference to analysis of thermal spectra characteristics of geological units from JHU spectral library, a new ASTER colored composite band ratio combination band 11/12: band 12/10: band 12/14 as R:G:B was applied successfully to distinguish quartz-rich felsic units and feldspathic rocks from the large meadow in the study area , with the band ratio and de-correlation techniques. To clarify the geological boundaries and remove the vegetation effect more effective, NDVI image and false color composite image composed of band 3: band 2 : band 1 visible to near infrared bands were also generated. The result indicated that combination of TIR FCC image, VNIR FCC image, temperature image and NDVI image for the study lithology mapping works well and matches the field geological