Application of Landsat multispectral scanner data and sediment spectral reflectance measurements to mapping of the Meatiq Dome, Egypt

Lithologic boundaries, structural elements and provenance of wadi sediments were determined for the Meatiq Dome in the central Eastern Desert of Egypt, using digitally processed Landsat multispectral scanner data in combination with laboratory spectral reflectance measurements. Optimally enhanced, principal-component color composite images were used to interpolate between field traverses in rugged terrain, to delineate contacts, and to clarify structural relationships in conjunction with extensive field work by Sturchio et al. Atmospherically corrected Landsat spectra were compared with petrographic data and laboratory spectral reflectance measurements, using a technique developed by Evans and Adams, to define the provenance of sediments in a wadi within the Meatiq Dome area. Contacts between the dome's granite and granite gneiss core, peripheral mafic mylonites, and the ophiolitic sequence outside the dome were distinguished. Small tonalite bodies were at the limits of discriminability but were mappable when the images were used in conjunction with field data. A large wadi within the dome exhibits interior drainage and carries only granitic-derived sediments, as distinct from a separate wadi system carrying a mix of materials. Coarseness of spectral measurements along with bias introduced by standard sample-preparation methods are the primary sources of error in the spectral comparisons, but the results obtained are consistent with the known geologic environment. The use of these techniques with corrected and optimally enhanced digital Landsat data proved to be a valuable added tool to field mapping efforts.