Holocene paleohydrological reconstruction of Lake Strzeszyńskie (western Poland) and its implications for the central European climatic transition zone

Abstract

Western Poland is located in the central European climatic transition zone, which separates the mild and humid Atlantic climate of Western Europe and the East European continental climate. This region is sensitive to lateral shifts of the European climate zones and is particularly suitable for reconstructing Holocene climate variability. This paper presents detailed analyses of the sedimentary record from Lake Strzeszyńskie since the Late Pleistocene. These include smear-slide and thin-section observations, X-ray fluorescence core scanning, magnetic susceptibility measurements, pollen analyses, and radiocarbon dating. The sediment record reveals three distinct sedimentary units consisting of: (1) an alternation of sand layers and laminated silt and clay deposits accumulated prior to 14,600 cal yr BP; (2) faintly laminated calcareous sediments intercalated with organic matter-rich layers deposited between 14,600 and 10,200 cal yr BP; and (3) massive calcareous mud deposited after 10,200 cal yr BP. The Holocene period is marked by nine phases of organicrich sedimentation and enhanced Fe deposition, which occurred at ca. 10.1, 9.3, 6.4-6.1, 5.5-5.1, 4.7-4.5, 2.7-2.4, 1.3-1.2, 0.8-0.6, 0.4-0.2 kyr cal BP. These phases are associated with high lake levels and correspond with wet periods recognized in several other records from Poland and central Europe. These phases partly coincide with North Atlantic cold periods, which may suggest that high lake levels are triggered by an ocean-continent linking mechanism.

Geology of the Morasko craters, Poznań, Poland—Small impact craters in unconsolidated sediments

“…A number of depressions currently host lakes of various shapes and sizes, filled with lacustrine sediments deposited since the time of dead ice degradation several hundreds to a few thousand years after the ice sheet retreat (Pleskot et al. ).…”

“…In the neighborhood of the moraines, many depressions have also formed as a result of the melting of dead ice blocks filling tunnel valleys or having been buried in glaciofluvial sediments (Stankowski 2008). A number of depressions currently host lakes of various shapes and sizes, filled with lacustrine sediments deposited since the time of dead ice degradation several hundreds to a few thousand years after the ice sheet retreat (Pleskot et al 2018). Tables S2 and S3 in supporting information with their coordinates).…”

“…Sediment cores recovered from the central part of crater A were composed of organic and lacustrine sediments overlying a thin sandy layer and Neogene clays (Stankowski 2008). Luminescence and radiocarbon dating (Stankowski 2001(Stankowski , 2008 and palynological research (Tobolski 1976) performed on the sediment core from crater A revealed that accumulation in the crater started not later than approximately 5000 yr ago, much later than in nearby lakes of glacial origin (Pleskot et al 2018). These results were strongly supported by the finding of paleosoil around crater A, which is described in detail below; the age of the paleosoil was assessed to overlap with the age of the oldest infill of crater A (Szczuci nski et al 2016).…”

Current perspectives on the capabilities of high resolution XRF core scanners

“…Accordingly, under drier and warmer climatic conditions the lake level drops. This causes higher concentrations of Ca and also of nutrients resulting in eutrophication with intensified calcite precipitation from the water column, while a shallower lake has oxygenated bottom waters and thus lower levels of Fe (Pleskot et al, 2018). These reconstructions correspond to other palaeorecords from Poland and to the lake-M A N U S C R I P T A C C E P T E D level reconstruction for Central Europe (Magny, 2004).…”

“…Holocene hydroclimatic variability was reconstructed using Ca/Fe for Lake Strzeszyńskie in western Poland (Pleskot et al, 2018). Ca is diluted in the sediments during wetter and colder periods due to the formation of a deeper lake, while Fe increases, at the same time, are caused by redox processes induced by the development of more anoxic bottom water conditions.…”