Landsat 8 (OLI) ETM+ satellite imagery data are evaluated for
improving and re-mapping the geologic map of Um Gheig area, Central
Eastern Desert of Egypt. Different remote sensing techniques including
FCC, band ratio, PCA, supervised classification and spectral
characteristic analysis were applied on satellite imagery to facilitate the
discrimination of the widely exposed Neoproterozoic basement rocks in
the study area. Best color composite 146 FCC, 762 FCC, band ratio 6/2,
4/3, 7/3 and 7/6, 6/5, 4/2 in RGB, as well as PCA 213 and 314 in RGB
were selected and used for detailed mapping of the different lithological
units. Spectral characteristic analysis was used to discriminate the rock
forming minerals through the different rock units in Umm Gheig area
(e.g. amphibole b7/b5, serpentine b5/b7, Quartz b7/b6, muscovite b6/b4
and PCA4). The rock units of Um Gheig area are divided four main
lithological units according to field and petrographical studies; ophiolitic
associations, foliated metavolcanics, post-granitoids and hammamat
sediments, as well as small parts of unmapple metavolcanics and
metgabbro. Ophiolitic associations are subdivided serpentinites,
metagabbro, volcanoclastic metasediments and hormblende schist.
Granitoids are subdivided El-Deilihimmi granite and Abu Shaddad
granite. Petrographically, serpentinites prevailing by antigurite
serpentinites, metagabrro includes quartz and hornblende gabbro, VCM
comprised different varieties range from biotite schist, biotite
hornblende schist, garnet biotite hornblende schist, intercalations of
actionolite schist and highly mylonitic schist, foliated metavolcanics
represented by schistose metatuffs and mylonitic schist, metavolcanics
represented by meta-andesite and fine metatuff, El-Deilihimmi granite
includes granodiorite and monzogranite while Abu shaddad granite
comprised alkali feldspar granite and syenogranite, hammamat
sediments represented by pebbles of dacite. A new modified geological
map is produced for Um Gheig area based on the remote sensing data,
field investigation and petrographical description.