Lithologic anomaly identification of hydrocarbon microseepages in Kelasu fold-and-thrust belt, West China using ASTER imagery

Evaluation of an Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image of the Kelasu fold-and-thrust belt, west china indicates that several important mineralization altered classes of hydrocarbon microseepages can be identified with good exposure by using ratio image and spectral-angle mapper methods. The resampled ASTER nine-band image data set VNIR+SWIR in 15m spatial resolution was corrected by FLAASH model and SWIR image data was calibrated by using in situ measurements of spectral reflectance. Subsequently, ASTER ratio images were employed for Al-OH, Fe²⁺, Fe³⁺ and CO₃ alteration extractions. For comparison purpose, in situ surface reflectance data were used to map alteration minerals which resulted from hydrocarbon microseepages, using spectral angle mapper method. The result shows that the distribution of the alteration rocks from the spectral angle mapper agrees very well with the alteration mineral extracted from the mineralogic ratio images for hydrocarbon microseepages altered rocks zone associated with petroleum using ASTER data. The result shows that ASTER data may provide independent parameters useful for regional petroleum exploration.