GRAIN SIZE ANALYSIS AREAL DISTRmUTION OP SEDIMENTS , ' AND ENVIHONMENT OP DEPOSITION Ol~ TIDAL AND BOTTOM SEDIMENT FROM GIIARDAQA REGION, RED SEA AREA.

GRAIN SIZE ANALYSIS AREAL DISTRmUTION OP SEDIMENTS , ‘ AND ENVIHONMENT OP DEPOSITION Ol~ TIDAL AND

BOTTOM SEDIMENT FROM GIIARDAQA REGION,

RED SEA AREA.

Y. A. ALI*, A. I. BELTAGY” AND LH. LOTFY”.
*Geology Department. Faculty of Science. Ain Shams University, Egypt.

**National InstItute of Oceanography and FIsherIes. Kayet Bay. AlexandrIa, Egypt.

ABSTRACT
The textur~ characterIstIcs of recent sedIments
In the Ghardaqa regIon of the Red sea shelf are
Investigated and compared with sImilar characteristics
of Recent tIdal and beach island sediments in the
same regIon. On going from the beach (tidal and.
Ishnd sedIments) towards the sea (shelf sedimtnti).
the mean she generally decreases lnd the sediment
type chlnges from coarse sand to muddy sand and
sandy mud. The sorting generally worsend. the skewness
values generally decreased, i.e. changed fram coarsly
skewed to very fInely skewed. Kurtosis values dId
not show any general trend of variation. The. areal
dIstrIbution of sand. silt and clay fraction indicates
that, on going from hnd ~owards the sea. the Sind
fraction decreased, sl1t fraction and clay fractIon
generally increased. This probably due eIther to
longshore currents (waves and win,ls) or to longer
transportatIon factors depending on the condition.
of the continental slope, t .e. topographic factors
of the sea” bottom. Furt~.rmore, distribution Map
of each fraction is drawn.
The discriminant functIon of Sahu (1964) for
envIronmental fnterpretation have been used.