REMOTE SENSING-BASED GEOLOGICAL MAPPING OF THE AREA WEST OF AL-MADINAH, SAUDI-ARABIA

The paper describes the methodology and results obtained during the geological mapping of the area north-west of the Holy city of Al Madinah Al Munawwarah in Saudi Arabia on the basis of Landsat Thematic Mapper data at a scale of 1:100000. The application of very sophisticated image processing algorithms yielded an image basis. The spectral units displayed were interpreted and then correlated to the lithological units along significant profiles during a field campaign. A thin section study of the rock samples supported the lithological classification. Generally, the region can be divided into two main geological units, namely the Precambrian basement rocks and the basaltic extrusive rocks of Harrat Al Rahat plateau which is covering the basement rocks in the east and the southeast. The basement rocks consist of a wide range of intrusive sedimentary and extrusive series, all metamorphorised with varying intensities. The lack of vegetation cover and the effective methods used in the remote sensing data interpretation allowed a practically clear distinction between the different lithological units, as verified during the field work. This result testifies to the high value of the application of remote sensing data in Saudi Arabia.