ENVIRONMENTAL CHANGES DURING THE BOREAL TRANSGRESSION IN THE NORTH-EASTERN WHITE SEA REGION (DETAILED CASE STUDY OF BYCHYE-2 SEDIMENT SECTION)
Author:
TALDENKOVA E.E.1, OVSEPYAN YA.S.2, RUDENKO O.V.3, STEPANOVA A.YU.4, BAUCH H.A.5
Affiliation:
1. Lomonosov Moscow State University 2. Lomonosov Moscow State University; Geological Institute RAS 3. Orel State University named after I.S. Turgenev 4. Paleontological Institute RAS 5. Alfred Wegener Institute for Polar and Marine Research
Abstract
Detailed multiproxy (lithology, micropaleontology, palynology) study of a 455 cm thick marine sediment sequence overlying the Moscovian till exposed in Bychye-2 section on the Pyoza River allowed for reconstructing past environmental changes during the Boreal transgression. Stratigraphic subdivision is based on the succession of local palynological zones that were correlated with previously established regional zones. The latter are constrained on the basis of correlation with the West European palynological zones. Marine sediments of Bychye-2 section accumulated from the end of the Moscovian glacial (>131 ka BP) until ca. 119,5 ka BP. Five ecological zones were established in the section in accordance with the upward trends in the changes in lithology and variability in the taxonomic composition of fossil assemblages of benthic foraminifers and ostracods and associations of marine dinocysts and freshwater green microalgae. Taken together, they are indicative of the progressive shallowing of the basin under the improving climatic conditions, which primarily influenced the degree of sea-ice cover extent. Three successive phases in the evolution of the Boreal transgression have been identified: 1) a seasonally sea-ice covered relatively deep freshened basin of the initial phases of flooding (455-360 cm, >131-130,5 ka BP); 2) a deep basin of the maximum phase of flooding with less extensive sea-ice cover (360-290 cm, 130,5-130,25 ka BP); 3) a shallow basin with reduced seasonal sea-ice cover (290-0 cm, 130,25-119,5 ka BP). The flooding of the territory with cold Arctic waters was rapid, as evidenced by the composition of microfossil assemblages represented by river-proximal Arctic species in combination with the species that prefer water depths of at least 40-50 m. The regression in the region started about 130 ka BP, which indicates that the glacioisostatic rebound of the territory was ahead of the global eustatic sea level rise. The most warm-water and taxonomically diverse assemblages of foraminifers and ostracods, containing species typical of the Baltic Sea, were recorded during the regressive stage, especially in the time interval of ~128-124 ka BP. This probably gives evidence for a rather long-lasting connection of the White and Baltic seas.
Funder
Russian Science Foundation
Publisher
Moscow University Press
Subject
General Earth and Planetary Sciences,General Agricultural and Biological Sciences,Geography, Planning and Development
Reference45 articles.
1. Abrukina R.E., Krasil’nikova G.N. [Foraminifers of marine interglacial deposits of the Kola-Karelia region, their stratigraphic importance and evolutionary history], Chetvertichnaya geologiya i geomorfologiya vostochnoi chasti Baltiiskogo shchita. Trudy instituta geologii. Karel’skii filial AN SSSR [Quaternary geology and geomorphology of the eastern Baltic shield. Proc. Institute of Geology. Karelian Branch AS USSR], 1972, no. 13, p. 39–58. (In Russian) 2. Bauch H.A. Interglacial climates and the Atlantic meridional overturning circulation: is there and Arctic controversy? Quat. Sci. Rev., 2013, vol. 63, p. 1–22, DOI: 10.1016/j.quascirev.2012.11.023 3. Bauch H., Erlenkeuser H., Fahl K., Spielhagen R.F., Weinelt M.S., Andruleit H., Heinrich R. Evidence for a steeper Eemian than Holocene Sea surface temperature gradient between Arctic and sub-Arctic regions. Palaeogeogr., Palaeoclim., Palaeoecol., 1999, vol. 145, p. 95–117, DOI:10.1016/S0031-0182(98)00104-7. 4. Beets D.J., Beets C.J., Cleveringa P. Age and climate of the late Saalian and early Eemian in the type-area, Amsterdam basin, the Netherlands, Quat. Sci. Rev., 2006, vol. 25, p. 876–885, DOI:10.1016/j.quasci-rev.2005.10.001. 5. Dalton A.S., Gowan E.J., Mangerud J., Möller P., Lunkka J.P., Astakhov V. Last In terglacial (MIS 5e) sea level proxies in the glaciated Northern Hemisphere, Earth Syst. Sci. Data, 2022, vol. 14, p. 1447–1492, DOI:10.5194/essd-14-1447-2022.
Cited by
1 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|