In the western part of the Gilf
Kebir and its foothills at the Libyan side is observe widespread conspicuous
red discolored areas on the satellite image. This area, beyond the Egyptian
border, is an intensively influenced by
hydro-volcanic activities during the Oligocene age
(Gilf Kebir crater field, Regenfeld pipes, Libyan desert glass etc.).
A striking feature is the "Red Spot". Here are the strata complete impregnated
by iron-containing hot solutions. Locally it should be noted that these
surfaces are covered with hardened ferruginous sandstone plates or detritus
on alluvial plains.
In the geological profiles of the hills and mountains in this region is
also to observe a several changes of these red layers with white sandstones.
Such a change is not necessarily coupled to the bedding planes in the
sediments.White sandstones also occur as clusters which break the stratification.
This is a clear indication of the
predicted hydrovolcanic processes that have led to a bleaching of the
sandstones. The possible chemical and mechanical processes are not explored.
The red and white sandstones occur
in principle everywhere, regardless of its stratigraphic position, but
regionally dependent. It is striking that mostly the lower parts of the
affected by the phenomenon
Except the Abu Ras passage east of Jabal Asa, and also near Wadi Sura,
in the lower parts of the Ordovician/Silurian sandstones, are changed
white sandstone to observe. Often they are covered with very ferruginous
Also upper parts of the plateau are
by the phenomenon of
(Wadi Abdel Malik). In principle, are the whole Gilf Kebir
(inclusive the southern part) and also the Abu Ballas scarp-contour in
the GKCF more or less affected by this phenomenon. Locally are to seen
again and again white parts in the sandstones. To this belongs also the
pushed zone of white erratic blocks in the northern part of the Gilf Kebir
(the so-called glaciogenic series).
Note: Another speciality
are red clayey layers within
strata in the Wadi Talh (western plateau along the Wadi Abdel Malik)
and in the western foreland at the Libyan side, which are also partially
exposed. These deposits are not formed secondarily. They document marine
floodings in the Carboniferous period.