FEATURES CONTROLLING RADIOELEMENTS DISTRIBUTION IN AL AGLAB REGION, NORTH EASTERN DESERT, EGYPT

This work is an approach to integrate multi-discipline set of data including geological and remote sensing
as well as airborne, ground radiometry and aeromagnetic geophysical data aiming to establish the controlling
features of the radioelement potential distribution within Al Aglab area. The investigated area of Al Aglab
region is located within the Northern Eastern Desert litho-structural domain where the outcropping rock types
comprise: metavolcanics (oldest), quartz diorites, Dokhan volcanics, Hammamat sediments and gabbrogranophyre
associations intruded by monzogranite, syenogranite and post granitic dykes (youngest). The
granitic rocks display sharp contact with the older pre-existing rock. The radioactive anomalies lay at the
intersections between NNW-SSE to N-S and NE-SW to ENE-WSW trending structure lineaments (joints,
faults and shear zones) within the syenogranites pluton of G. Al Aglab and along the NE-SW to ENE-WSW
trending felsitic dykes, jasperoid veines and pegmatite bodies.
Landsat Thematic Mapper (TM) remote sensing map in great concordance with airborn gamma ray
spectrometric data delineate most of the surface geology over the compiled geological map. The extracted
structural lineaments are coherent to those inferred from the analytical signal magnetic maps in complete
harmony with the NNW-SSE to N-S and NE-SW to ENE-WSW trending fault systems obtained from the
ground geological and radiometric investigation. Moreover, different types of alterations such as hematitization,
Kaolinitization, chloritization and silicification are recorded within the synogranite, where their distribution
is mainly controlled by the intersections between the NNW-SSE to N-S and NE-SW to ENE-WSW trending
structural lineaments.
The studied structural lineaments are arranged according to three main trend clusters around NNW-SSE
to N-S, NE-SW to ENE-WSW and NW-SE to WNW-ESE directions representing the main factor controlling
the emplacement of the different granitic intrusions in Al Aglab area. Moreover, most of these lineaments, as
obtained from field measurements, show strike-slip movement criteria within an extensional context. All the
recorded mineralized occurrences are related to extensional events that create the necessary space either for
mineral entrapment and/or the percolation of the hydrothermal carrying solutions along these structural trends
especially at their intersections.
Spectrometric data (K, U and Th) shows a very high consistency between the radioelement distributions
and the differentiated outlines of different rock types. Results from integrated field studies, Landsat Thematic
Mapper (TM) remote sensing data and geophysical data analyses provide important constraints on the tectonic
evolution of Al Aglab area and importantly, demonstrate the strength of combining remote sensing data with
geophysical data and geological observations in resolving the surface geometry of major fault systems and
their impact on the radioelement potential distribution within Al Aglab area.