Thermal infrared data analyses of Meteor Crater, Arizona: Implications for Mars spaceborne data from the Thermal Emission Imaging System

Abstract

Thermal infrared (TIR) data from the Earth‐orbiting Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument are used to identify the lithologic distribution of the Meteor Crater ejecta blanket. Thermal emission laboratory spectra were obtained for collected samples, and spectral deconvolution was performed on ASTER emissivity data using both image and sample end‐members. Comparison of the spaceborne ASTER data to the airborne Thermal Infrared Multispectral Scanner (TIMS) data was used to validate the ASTER end‐member analyses. The ASTER image end‐member analysis agrees well with past studies considering the effects of resolution degradation. The work at Meteor Crater has direct bearing on the interpretation of Thermal Emission Imaging System (THEMIS) data currently being returned from Mars. ASTER and THEMIS have similar spatial and spectral resolutions, and Meteor Crater serves as an analog for similar‐sized impact sites on Mars. These small impact craters have not been studied in detail owing to the low spatial resolution of past orbiting TIR instruments. Using the same methodology as that applied to Meteor Crater, THEMIS TIR data of a provisionally named Winslow Crater (∼1 km) impact crater in Syrtis Major are analyzed. The crater rim and ejecta blanket were found to contain larger block sizes and a lower albedo than the surrounding ejecta‐free plain, indicating a young impact age. The composition of the rim, ejecta, and surrounding plain is determined to be dominated by basalt; however, potential stratigraphy has also been identified. Results of this work could be extended to future investigations using THEMIS data.