Holocene marine ingressions in the coastal zone of the pomeranian bay based on radiocarbon assays

Abstract

Abstract:In recent years, a team at the Geology and Paleogeography Unit, Marine Sciences Institute, University of Szczecin, has been performing geological, geochronological and paleogeographic surveys in (i) the Szczecin Lagoon and Świna Gate Sandbar and (ii) the estuary section of the Rega river valley near Mrzeżyno. These studies have helped to examine and identify not only the distribution of fossil marine sediments but also their lithological and sedimentological characteristics. The age of marine ingressions and regressions in the coastal zone of the Pomeranian Bay were determined using approximately 170 radiocarbon assays. It was found that the marine ingression associated with the 'Littorina transgression' was not synchronous at these two areas. It started earlier in the Mrzeżyno area, ca. 8300-8200 cal BP. In that first phase, marine sediments developed as tightly packed sands containing a few fragments of shells. In several profiles, these deposits were separated from the bottom and top with layers of peat, thus allowing an indirect determination of their age. The next phase of ingression began about 7300 cal BP. These younger marine sediments already contained quite numerous shells of marine malacofauna, especially Cardium glaucum, often found in a life position. In the area of the Szczecin Lagoon and Swina Gate Sandbar, the oldest marine ingression started as early as about 7350 cal BP. The quite clear trace is a considerably thicker series of marine sands with numerous sea shells representing marine and brackish-marine environments, including Cardium glaucum shells in a life position, which made it possible to identify the age and the rate of accumulation of marine sands.

Holocene relative sea-level changes in the eastern part of Pomeranian Bay and the Szczecin Lagoon, Southern Baltic Sea

“…(Borówka et al, 2005). However, existing data (Borówka and Cedro, 2011; Borówka et al, 2005, 2012, 2017; Goslar et al, 2009) indicate the lack of evidence for marine or brackish conditions in the Szczecin Lagoon area before ca. 7200 yr b2k (the age of the oldest marine shell located at a depth of 7.13 m b.s.l.…”

“…From the Oldest Dryas to the beginning of the Northgrippian, peatbogs and lakes occurred in the Szczecin Lagoon area (Borówka and Cedro, 2011; Borówka et al, 2005, 2012, 2017), as was in the Pomeranian Bay area. The beginning of the marine transgression into the Szczecin Lagoon area is also poorly documented.…”

“…In the study area, radiocarbon dating was performed for deposits from drillings located in the Pomeranian Bay, including the Odra Bank (Jurowska and Kramarska, 1990; Kramarska, 1998; Kramarska and Jurowska, 1991, unpublished data in Polish Geological Institute – National Research Institute archive) (Figure 2a), Szczecin Lagoon and Świna Gate barrier (e.g. Borówka et al, 2005; Goslar et al, 2009; Latałowa, 1992; Prusinkiewicz and Noryśkiewicz, 1966; Wypych, 1980) (Figure 2b), sites along the coast between Niechorze and Kołobrzeg (Brykczyńska, 1978; Dobracki and Zachowicz, 2007; Kopczyńska-Lamparska, 1976; Masłowska et al, 2003; Sydor and Kotrys, 2013; Sydor et al, 2015; Szeroczyńska, 1985; Tomczak, 1995) (Figure 2c) and Rega River mouth (Borówka and Cedro, 2011; Cedro, 2012, 2016; Dobracka, 1990, 1992; Piotrowski et al, 2017; Witkowski et al, 2009) (Figure 2d).…”

“…The Szczecin Lagoon was widely investigated and many radiocarbon dates are available (e.g. Borówka et al, 2005Borówka et al, , 2012Borówka et al, , 2017Borówka and Cedro, 2011;Goslar et al, 2009); however, a sea-level curve has never been developed. During the last years, Pomeranian Bay was also geologically mapped (Kramarska et al, 2016) and many new radiocarbon data become available.…”

Age and evolution of the Littorina Sea in the light of geochemical analysis and radiocarbon dating sediment of cores from the Arkona Basin and Mecklenburg Bay (SW Baltic Sea)

“…The age of the first inflows of Littorina transgression differ between studies from different areas. The follow-ing are the datings of the first signs of the marine environment: 8650 cal BP in Wismar Bay (Schmolcke et al 2006), 8640 cal BP in Rega River Valley (Witkowski et al 2009), 8550 cal BP on the Gardno-Łeba Plain (Rotnicki 2009), 7360 cal BP in the Szczecin Lagoon (Borówka et al 2005, Borówka, Cedro 2011 on the Polish coast, 8500 cal BP in southern Sweden in Blekinge (Berglund et al 2005), and 7200 cal BP in the Arkona Basin (Rößler et al 2011).…”