MINERALOGICAL AND RADIOACTIVE STUDIES FOR UTILIZATION OF LAKE NASSER SEDIMENTS

The present study gives a trial to enhancement the management of Lake Nasser (LN) sedimentsand presents a demonstration of the sediments assessment process through focusing mainly on thesedimentological, minerlogical and radiometric characteristics of LN and the adjacent beach sediments.The study revealed that the increasing of sediments accumulation rate at LN cause many challengesand problems which change the morphological features and formation of the flood plains and innerislands. The occurrence of sediment accumulations and heavy mineral placers in LN onshore sediments isknown but no systematic attempts has so far been made to management and explore these heavy minerals.The detailed mineralogical and g-spectrometric studies for Lake Nasser sediments revealed thatthe grain size distribution in bottom samples dominant by sandy-silty clay in contrast of silty clayeysand and clayey silty sand in the eastern and western banks, respectively. Heavy fraction in the bottomsediments of LN and the adjacent beach indicates relatively low concentrations of the economic heavyminerals (magnetite, hematite, ilmenite, leucoxene, rutile, zircon, garnet and monazite) that varies between0.61% and 1.22% for LN offshore sediments and ranged between 1.40% and 1.73% for the eastern beachsamples where the western beach samples record 1.30% and 1.73%. It follows that their industrialexploitation is not economically profitable, in spite of previous exploratory studies in the survey zone.The radiometric analysis of all samples showed weak level of radioactivity. Lake Nasser bottom samplesshowed higher radiometric measurement relative to the adjacent beach samples. This may be attributedto the occurrence of monazite in the LN fine sediments that reach up to 0.0039% and also the presence ofsome metamict zircon.The proposed solution for lake sedimentation problems is to prevent eroded particles from enteringthe lake in the first place by mechanical dredgers. Utilization of economic minerals occurrence in LN canbe facilitated by dredging mud into the lake banks. The mud fertility of the reclaimed landin the area.This process also stops sand dunes progression especially in the western bank.