GEOLOGIC AND RADIOMETRIC STUDIES OF SEDRI-UM TOMYEM AREA, SOUTHWESTERN SINAI, EGYPT

The Paleozoic basin exposed sediments in Sedri-Um Tomyem area is considered a part of a uranium promising district in the northern part of south Sinai. The study area is a part of this promising district. It is bounded by long. 33o 21’ 09" - 33° 21’ 27" E and lat. 28° 53’ 08" - 28° 53’ 33" N. and classified stratigraphically into three main
stratigraphic units that include from base to top, Lower Sandstone Series, Carboniferous Limestone Series (Um Bogma
Formation), Upper Sandstone Series (Abu Thora Formation). The Lower Sandstone Series is classified into three
formations from base to top as Sarabit El Khadim Formation, Abu Hamata Formation and Adedia Formation of the
Cambro-Ordovician period. In the scope of uranium mineralization, Adedia and Um Bogma Formations have the
priority and are considered the main target for uranium ore prospecting and exploration. The study area contains high
content of uranium (more than 1300 ppm U), copper and iron-manganese minerals and other trace elements.
The gamma-ray spectrometric survey has been conducted in the study area along a number of profiles directed N-S. The spacing between the survey lines was set at 50 m, while the interval between stations was 20 m, with a profile length of about 900 m. The gamma-ray spectrometric maps show different levels over the area, which reflect contrasting radioelement contents for the various exposed rock types. The highest radio-spectrometric levels are located along the northwest-southeast trend and of some scattered parts all over the study area. They are mainly associated with Um Bogma Formation outcrops. The area possesses gamma radiation ranging from 0.8 and 35.6 Ur as a total count, 0.1 to 2.5 % K40, 0.1 to 42.3 ppm eU, 0.7 to 36.6 ppm eTh , in addition to some anomalous zones of uranium which show values greater than 1300 ppm eU. A uranium composite image map is constructed to identify and outline the uranium anomalous zones. This map indicates that seven anomalous uranium occurrence zones of relatively wide extension have been delineated and can, therefore, be used as exploration leads for additional uranium deposits