Regional Scale Lithologic Mapping in Western Tibet Using Aster Thermal Infrared Multispectral Data

Lithologic mapping in the hostile and inaccessible mountainous region like the Himalaya and Tibet has frequently been a great challenge for geologists. The remote sensing techniques should be a potential player in lithologic mapping and structural analysis in these mountainous regions. With the successful development of minrealogic indices, e.g., Quartz Index (QI), Carbonate Index (CI), Mafic Index (MI) based on the ASTER multispectral thermal infrared (TIR) data, which have demonstrated the usefulness and effectiveness of ASTER TIR data on lithologic mapping in the semi-arid to arid regions, we began to develop a lithologic mapping system since 2005. The system can store some necessary information for data searching and provide a priority order determination for the scenes covering the specified region. Also, it can calculate the mineralogic indices and generate the lithologic mapping images to cover the target region. This lithologic mapping system was successfully applied to lithologic mapping in some target regions in western China. We employ continuously ASTER TIR multispectral data for lithologic mapping in the western Tibetan Plateau, in which the geologic mapping is a great challenge for the human beings because the average elevation in this region is over 5000 m above sea level in 2009 JFY. Here, we show the regional scale lithologic mapping result. Detailed lithologic mapping and geologic analysis of ASTER multispectral data in this region will improve our understanding of the evolution of the India-Asia collision.