Core Sediments from Lake Brollus (Bahra el Burullus), Egypt

Nine short cores were taken from different regions of Lake Brollus, an Egyptian large shallow brackish-water Delta lake connected with the Mediterranean Sea. The core samples were subjected to some investigations in order to know the vertical variations in the values of different constituents of the deposits. The variations of water content of the sediments are mainly due to the nature and type of these sediments. An inverse relation was found between the density of wet mud and the water content of some core samples. The sediments of the lower parts of the cores taken from the central region of Lake Brollus were enriched with organic matter and black in color. These black sediments may be remains of dense land vegetation entered into Lake Brollus by drainage and fresh water. They may be also remains of massive plankton organisms which survived for a long period in this lake under favourable conditions. The amounts of diatom-silica estimated from the sediments can be used as a rough indicator for the amounts of diatoms which were found in the lake at the time of deposition. The allochthonous materials, the organic matter, the calcareous substances and the diatomsilica generally were deposited in variable amounts at various depths of the cores. The quantitative distribution of these components in the core sediments was found to depend mainly upon certain factors which were discussed.