Extraction of Mineral Alteration Anomaly Zone from Aster Data in Manzhouli, China

All sorts of anomaly graphs of physical geography and geochemistry, such as aeromagnetic anomaly graphs, bouguer gravity anomaly graphs, regional geochemical anomaly graphs and so on, are all parameters for exploration deposit. And following the remote sensing image shortwave and infrared bands coming, researchers of remote sense have engaged in many highly effective experiments and have approved that there are high relativity between altered rocks information and metal deposit. So hydrothermal alteration information extracted from remote sense information can be as an important exploration mine sign. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is an advanced multispectral imager and covers a wide spectral region with 14 bands, which are 3 bands between 0.52 and 0.85 m , 6 bands from 1.6 to 2.43 m and 5 bands in the 8.125to 11.65m wavelength region with 15-m, 30-m and 90-m resolution respectively, from visible to thermal infrared with high spatial, spectral, and radiometric resolution [1]. The VNIR, SWIR and TIR wavelength regions provide complementary data for lithologic mapping [2] and geological application [3]. The Manzhouli area, Inner Mongolia in China mineralized study area, is underlain by a hydrothermally altered rocks zone associated with Ag-Pb-Zn deposits mineralization. The purpose of this study was to evaluate ASTER data acquired on August 22, 2004, for recognizing and extracting alteration anomaly zones in the study area. The paper firstly discusses the spectral features discernable in laboratory and field spectra of the Orefield spectra convolved to ASTER spectral resolution. And then the relationship between lithologic composition and spectral features of the field samples is founded. Following above, hydrothermally altered rocks classification are analyzed based on use of the ASTER image data.