FACIES CHARACTERISTICS AND GEOGRAPHIC DISTRIBUTION OF RHODOLITHS AND MAERLS (RED ALGAE) IN SOUTHERN SHELF OF THE SEA OF MARMARA

Abstract

Irregular crusts, rhodolith and maerl facies of crustose coralline red algaes were determined in the recent sediments of southern shelf of Marmara sea. Rhodoliths are found in western off shore of the Kapıdağ peninsula at a depth of 27-52.5 m. They have a diameter of 1-8 cm and are composed of Lithothamnion corallioides Crouan and Crouan (1867). They exhibit different growth shapes depending on the environmental conditions and may be found as laminated, nodular, and ball shapes in high-energy, shallow (0-30 m) aerated waters. Maerls are also composed of Lithothamnion corallioides. In between Kapıdağ and Bozburun peninsulas and a depth of 27-52.5 m, they are observed as free, open branch, spheroidal, ellipsoidal, and discoidal shapes. Phymatolithon calcareum Adey and McKibbin (1970) is another species of red algae. It forms irregular crusts coiling around the rock fragments, pebbles, and corals. Rhodolith-bearing sandy and large pebbled, maerl-bearing sandy and coarse pebbled, and skeletal sandy facies were described in these rhodolith and maerl-bearing deposits. In addition to these facies, two other facies of bryzoa and serpulites were also determined. Crustose coralline red algaes and their depositional environments in the southern shelf of Marmara sea indicate that Mediterranean conditions have prevailed in the sea of Marmara during the interglacial periods along Quaternary and even in the recent time.