THE DISTRIBUTION OF CALCIUM CARBONATE IN CONTINENTAL SHELF SEDIMENTS OF MEDITERRANEAN SEA NORTH OF THE NILE DELTA IN V.A.R.

THE DISTRIBUTION OF CALCIUM CARBONATE

IN CONTINENTAL SHELF SEDIMENTS OF MEDITERRANEAN

SEA NORTH OF THE NILE DELTA IN V.A.R.

By
YEHIA M. ANWAR MAMDOUH AnDEL -MAKSOUD MOHAMED
Hcad of Geology Dept Assistant Researcher
Faculty of Science, I nstitute of Oceanography
Alexandria University. & Fisheries Alexa ndria.

ABSTRACT
Calcium carbonate is an important material necessary for building the skeletons of aquatic animals and is also considered as the chief source of ancient
calcareous deposites.
The present studies have been undertaken to determine the nature and the
distribution of carbonate content in the continental shelf sediments North of the
delta, in relation to the topography of sea floor, the’influceve of the river Nile
draining into the sea and other environmental factors.
(A) Preparation of samples for analysis:
Fifty samples representing the area under investigation were analysed for
carbonate content (Fig. 1) About 30 grams from each sample were soaked in distilled water, stirred and then let to stand overnight. The supernatant liquid was
then siphoned aLd the ()peration was repeated. The samples afterwards were
dried in an oven at 105°0. The washed and dried samples were finally powdered
to pass through a 120 mesh sieve using an automatic mortar and were preserved
in clean and well stoppered containers for analysis.
(B) Method of analysis:
The carbOLate content (including both calcium. ar.d magnesium c~nbonate)
was determined in the powdered samples according tiO t,he method describedbyU.
S. D. A. 1954 and summarized as follows:
I.-Place 5 grams of t,he sample in 250 m.l. beaker, add 100 m!. of 0.5 NRc1
by means of a pipette, cover with wat,ch glass and boil gently for 5 minutes, cool,
filter and wash all the acid from the residue with distilled water.
2.-Determine the amount of un-used acid by adding 2 drops of phenolph~
thaleine and back titrating with 0.25 N NaoH.
3.-The same procedure was carried out on a dried pure calcium carbonate
instead of the sample and the amount of unused acid was det.ermined which is
equivalent to 100% of calcium carbonate.