Environmental reconstructions of Eemian Stage interglacial marine records in the Lower Vistula area, southern Baltic Sea

Abstract

A multiproxy study of Eemian Stage sediments in two core records, Licze and Obrzynowo, in the Gulf of Gdańsk area of northern Poland, shows that the brackish‐marine interglacial conditions were determined partly by regional environmental changes and partly by local changes of the river outflow from the Vistula into the southern Baltic Sea. Correlation of the sediments with the Eemian is based on pollen analysis of the Obrzynowo record, showing the presence of regional pollen zones (RPAZ) E2–E6, combined with previously published pollen analyses from Licze (RPAZ E1–E7). A floating chronology is established on the basis of correlation with the annually laminated Bispingen sequence. Diatoms, foraminifera and ostracods are used as marine environmental proxies at both sites. An indication of marine conditions as early as pollen zone E1 or E2 at Licze and close to the E2–E3 boundary at Obrzynowo reflects the rapid relative sea‐level rise in the area, which proceeded through ∼3000 years. A major salinity increase c. 1100 years after the beginning of the Eemian (early pollen zone E4) at both sites may be related to the opening of the Danish Straits. The Obrzynowo site became isolated from the sea at c. 3500 years (early pollen zone E5), whereas marine conditions continued at Licze until c. 7000 years, that is, throughout pollen zone E5. Gradually shallower water after c. 5000 years presumably resulted from progradation of the rivers combined with isostatic rebound of the area before final isolation from the sea at c. 7000 years.

Quaternary stratigraphy and palaeogeography of Poland

“…The end of the interglacial was recorded by development of a spruce-fir forest, alder (Alnus) on wetlands and followed by a pine forest with admixture of birch (Betula) in an unstable climate (Kupryjanowicz et al 2016). In the Lower Vistula region a transgression of the Eemian sea occurred (Makowska 1986;Head et al 2005;Knudsen et al 2012;Marks et al 2014). In loess sections this interglacial was recorded by the palaeosol GI1 (Maruszczak 1991).…”

Reconstructing Holocene temperature and salinity variations in the western Baltic Sea region: A multi-proxy comparison from the Little Belt (IODP Expedition 347, Site M0059)

“…Its history is highly 140 dynamic and governed by the regional isostatic rebound and global sea level changes resulting in alternating freshwater and brackish phases and complex shoreline development (e.g. Björck, 1995Björck, , 2008Knudsen et al, 2011;Andrén et al, 2011). The time interval investigated in this study comprises the transition from freshwater conditions to the brackish-marine conditions of the Littorina Sea stage.…”

Site M0060

“…Taxonomic composition of this assemblage in combination with the presence of dropstones in this interval (see "Lithostratigraphy") suggest cool-water marine conditions (Seidenkrantz, 1993b;Seidenkrantz and Knudsen, 1993). The presence of E. williamsoni may suggest shallow or intertidal waters (Knudsen et al, 2012) or transport of foraminifers from a nearby environment of this type.…”