Reconstruction of relative sea-level changes based on a multiproxy study of isolated basins on the Onega Peninsula (White Sea, northwestern Russia)статьяИсследовательская статья
Статья опубликована в журнале из списка Web of Science и/или Scopus
Аннотация:This study presents the results of lithological, diatom, geochemical analyses and radiocarbon chronology of the bottom lake sediments and peat bogs in the central part of the Onega Peninsula (the southern coast of the White Sea): Lake Maloye Murakanskoye (11.0 m a.s.l.), Lake Zhirovskoye (9.5 m a.s.l.), Lake Murakanskoye (7 m a.s.l.), and the Gorbovatiy Mokh bog (6.5 m a.s.l.). The bottom topography and sediments of Lake Murakanskoye were examined using sonar and ground penetration radar (GPR) survey, whereas in the other locations only the water depth was measured. Then, the digital models of the lake bottom topography were created. As an additional indicator of the relative sea-level (RSL) position, we used data on the altitude of the coastal terraces. Evidences of two transgressions in the White Sea (late glacial and Middle Holocene) are revealed. The transgressions were interrupted by two regressions (Early and Late Holocene). Our studies do not allow us to make a clear conclusion about the time and maximum level of the late glacial transgression. However, we may suggest that its level was above 11 m a.s.l. The regression of the Early Holocene started before 10.6–10.2 ka cal BP when the water level in the study area dropped below the altitude of 11m. At 9.4–9.1 ka cal BP the RSL was at an altitude of ca 7m. The Middle Holocene transgression (Tapes) started after 8.4 ka cal BP. The maximum level was reached before 7.4 ka cal BP and did not exceed an altitude of 9.5 m. The RSL stabilized at an altitude about 8.5–8 m during 7.4–6.0 ka cal BP. During 6.0–3.9 ka cal BP RSL very slowly decreased or fluctuated by the level of 8–7 m. RSL began to fall from the 7 m altitude about 4.0–3.9 ka cal BP and by 2.7–2.3 ka cal BP the sea-level reached 4.5 m. After that RSL dropped to its modern position. During the last 4.0 ka cal BP the rate of RSL fall was approximately 0.17–0.18 cm/year.(The research was carried out with the financial support of the Ministry of Education of the Russian Federation (project No. FSZN-2020-0016) (paleolimnological research), the state assignment No. FMGE-2019-0005 of the IG RAS (geomorphological research, creation of DEM), the state assignment No.FMWS-2019-0008 of the IG RAS (radiocarbon dating and date processing), the implementation of grain size and geochemical analyses were realized by the KOPRI fellowship 2019 support, the topics of the State Program No. 121040100323-5 (field geomorphological and DGPS survey, creation of DEM), the State Program No. 121051100167-1 (diatom analysis), the RUDN University Strategic Academic Leadership Program (GPR research)).
