Stratigraphic
sedimentology and lineaments of ElQalamun area, north Western Desert, Egypt
Morsy A. Morsy and Ahmed F. Kamel
Nuclear Materials Authority, Cairo, Egypt |
The main rock facies exposed in ElQalamun SW
Fayum depression belong to the Middle Eocene Qalamun Fm forming the main scarps and ridges
in the area. The rugged surfaces of the plateaus and the low plains are covered with Early
Miocene sand-silt and Quaternary gravels including Fe oxide and basalt fragments. The
Middle Eocene and Oligocene beds exhibit good horizontal stratification and continuity,
slight dipping (2o-3o) in places and gentle anticlinal fold with N25o W axis. Faults of NW, NNW and WNW direction also traverse the
area.
ElQalamun Fm has three main cycles of deposition represented by shale-marl cycle at the
base, followed upward by the chalky-marl cycle and the limestone-marl cycle.
The Middle Eocene rocks show uranium content of 5-8 ppm, while those of the Oligocene,
Early Miocene and Quaternary sediments reflect slightly higher uranium content 9-14 ppm.
The origin of uranium is syngenetic in the Mid Eocene sediments and redeposited in the
Oligocene and Early Miocene sediments. Bands of iron oxides (2-20 cm) intercalate the
Middle Eocene and Oligocene beds, and have between 15.2 % and 73.6 % Fe2O3.
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