New data about age, structure, faunal composition of marine sediments in the vicinity of St. Petersburg

Abstract

The complex results of the study of the 5 sites with the middle and late Pleistocene marine sediments are discussed. Sixteen marine and freshwater mollusc and eight marine foraminifera species were found in the three Mga stage localities in the vicinity of St. Petersburg. Forms of western Arctic origin dominate within these complexes. Eight molluscs species were found here for the first time: Arctica islandica (Linn.), Macoma balthica Linn., Musculus niger (Gray), Modiolus modiolus (Linn.), Margaritifera margaritifera Linn., Pisidium amnicum (Mull.), Sphaericum solidum (Norm.), Corbicula fluminalis (Mull.). These fauna inhabited in narrow shallow-water boreal marine and partly freshwater basins, which were connected with the Arctic Ocean during the late middle and late Pleistocene. Marine sediments with IR-OSL ages of 21.1 ka and 20.3 ka and paleontological characteristics were found in two sections near St. Petersburg at the heights of 20-130 m above modern sea level.