Upper Pleistocene and Holocene stratigraphy in the Kola Peninsula and Northern Karelia (N–W Russia): Marine and glacial units

Abstract

Data on litho- and biostratigraphy of major sedimentary sequences and their geochronological records were compiled and summarized to describe the Late Pleistocene–Holocene marine and glacial events in the Kola-Northern Karelia region. In the coastal Kola Peninsula and its inner part, three marine units and two glacial events were identified in the Upper Pleistocene sequences. The first marine unit (Ponoi Beds in the regional stratigraphy) can be definitely referred to the significant Late Pleistocene transgression known as the Boreal in northern Eurasia. Data on the Kola Peninsula show that the warm-water Boreal transgression was longer than the Eemian one in western Europe, comprising at least MIS 5e-d (from 130–120 to 105–100 ka BP) in the White Sea depression and MIS 5e-c (earlier at least 90 ka BP) in the Barents Sea. Forested environments dominated on the Kola Peninsula at that time. The second Interglacial marine unit (Strelna Beds) attributed to the subsequent Belomorian transgression was deposited in relatively cold settings at the final phase of the Mikulinian Interglacial (MIS 5), about 100 to 70–80 ka BP. Adjacent areas were covered with open forest and tundra. The third marine unit referred to the Interstadial Leningrad Group was formed 60–40 ka BP in rather a cold marine reservoir, when the environmental conditions were more severe than now. The Late Pleistocene glacial events are correlated to the Podporozhie and Ostashkov Groups (MIS 4 and 2). The Podporozhian glacial unit seems to be associated with the Barents-Kara Ice Sheet and its melting caused the glacioeustatic transgression in the White Sea during the Leningradian Substage (MIS 3).During the Late Glacial and Holocene, a periglacial freshwater lake, brackish-water basin and marine reservoir successively appeared in the White Sea depression successively. Two marine events are suggested here based on the key sedimentary sequences from the coastal isolated lake, i.e. the Late Glacial transgression and the early-middle Holocene (Tapes) transgression.