INTEGRATION OF LANDSAT-8 AND AIRBORNE GAMMA-RAY SPECTROMETRIC DATA FOR GEOLOGIC MAPPING OF KAB AMIRI AREA, CENTRAL EASTERN DESERT, EGYPT

Kab Amiri area in the Central Eastern Desert of Egypt comprises a variety of basement rocks
including ophiolitic mélange (serpentinites and metasediments), metavolcanics, older granitoids and
younger granites. In this study, Landsat-8 image processing and airborne gamma-ray spectrometric data
were integrated to discriminate and mapping lithological units. The applied image processing including
Optimum Index Factor and data transformation techniques such as band ratios and principal component
analysis in addition to supervised classi􀂿cation were effective in discrimination the different rock units
especially the younger granites into two verities. The radioelement maps are correlated with the processed
Landsat-8 images to delineate different rock units and their radioactive penalties. They show a limited
capability in geological mapping compared with Landsat-8 image processing. They discriminate the
younger granites and older granitoids (relatively higher radioactivity) from the other rock units (relatively
lower radioactivity), but they failed to discriminate between the two varieties of the younger granites. Gabal
Kab Amiri granitic pluton possesses the highest radioactivity in the area relative to the other rock units.
Landsat-8 image processing results are con􀂿rmed by detailed 􀂿led work and petrographic investigation.
The petrographic investigation revealed that the younger granites are represented by monzogranites and
syenogranites, whereas the older granitoids are represented by granodiorites. A detailed geologic map of
scale 1:50,000 is constructed from the interpretation of the processed Landsat-8 images, airborne gammaray
spectrometry, 􀂿eldwork and petrographic studies. Consequently, remote sensing is recommend as a
rapid and cost effective tool for mapping lithological units in arid regions.