MINERALOGICAL AND RADIOACTIVE STUDIES FOR UTILIZATION OF LAKE NASSER SEDIMENTS

The present study gives a trial to enhancement the management of Lake Nasser (LN) sediments
and presents a demonstration of the sediments assessment process through focusing mainly on the
sedimentological, 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 challenges
and problems which change the morphological features and formation of the flood plains and inner
islands. The occurrence of sediment accumulations and heavy mineral placers in LN onshore sediments is
known 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 that
the grain size distribution in bottom samples dominant by sandy-silty clay in contrast of silty clayey
sand and clayey silty sand in the eastern and western banks, respectively. Heavy fraction in the bottom
sediments of LN and the adjacent beach indicates relatively low concentrations of the economic heavy
minerals (magnetite, hematite, ilmenite, leucoxene, rutile, zircon, garnet and monazite) that varies between
0.61% and 1.22% for LN offshore sediments and ranged between 1.40% and 1.73% for the eastern beach
samples where the western beach samples record 1.30% and 1.73%. It follows that their industrial
exploitation 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 samples
showed higher radiometric measurement relative to the adjacent beach samples. This may be attributed
to the occurrence of monazite in the LN fine sediments that reach up to 0.0039% and also the presence of
some metamict zircon.
The proposed solution for lake sedimentation problems is to prevent eroded particles from entering
the lake in the first place by mechanical dredgers. Utilization of economic minerals occurrence in LN can
be 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.