Lithological and petrographic features of tills in the Koźmin region and their value for stratigraphical interpretation of glacial Lake Koźmin deposits, Central Poland

Abstract

In the middle section, the Warta River valley runs through the Adamów graben. Th e graben was characterized by subsidence since the end of the Paleogene and favoured accumulation during the Neogene and the Quaternary. Th e Quaternary deposits consist of several till horizons separated mainly by a series of fl uvioglacial sand and a thick series of glaciolacustrine sediments. Th e research was concentrated on three upper levels of tills and selected series of sand available in Koźmin and Koźmin-Północ "Adamów" opencast mines. Th e lithological, petrographical features and long-axis azimuth of pebbles were analyzed. Th e results showed that the lower till could be dated to the Elsterian, middle till to the Wartanian, and the upper till is probably also Wartanian. Glaciolacustrine deposits which fi lled the erosional form and appeared in the middle till correlate with the end of the Wartanian.

Origin of the Baltic Sea basin by Pleistocene glacial erosion

“…The estimated 25% contribution from erosion of local bedrock within the sink area is more uncertain and requires further testing. The carbonate content of tills in Poland is highly variable (Woźniak et al 2009;Morawski 2009;Czubla et al 2010) and the leakage losses of carbonate in solution may be too low. On balance, the volume of sediment eroded from the BSB is likely underestimated.…”

“…The sediment volume includes rock derived from erosion within the sink area. This local erosion is manifest in the presence of local rocks as clasts in tills (Czubla et al 2010), by glacitectonic rafts of these rocks (Aleksa & Bitinas 2000;Obst et al 2017) and by extensive networks of tunnel valleys cut by glacial meltwaters into bedrock (Ehlers 1981;Al Hseinat & Hübscher 2014). This local erosional contribution is large.…”

“…Solute load is lost to meltwater and so represents a missing part of the material eroded from the source area where meltwater can escape from the sink area. Losses to solution in soils are evident from the Geological Atlas of Poland (Nawrocki & Becker 2019) which gives mean Ca concentrations of 0.5 % in top soil and 1.67% in surface sediments that compare to Ca concentrations of 5-10 % at depth in the matrix of Saalian and Elsterian tills (Czubla et al 2010). We adopt 10% as a conservative estimate for total losses of carbonate in solution from the sink area.…”

Unravelling the complex nature of the Upper Weichselian till section at Gdynia Babie Doły, northern Poland

“…This is due to the fact that in the area north and northwest of Babie Doły Quaternary deposits are isolated from the Cretaceous and Paleogene substrate by soft and/ or fine-grained Miocene and Pliocene sediments (Leszczyński, 2012). The Quaternary sediments, including the older glacial deposits, might have furnished additional protection, as documented by several authors (e.g., Kjaer et al, 2003;Czubla, 2006;Czubla et al, 2010Czubla et al, , 2013. In our view, the content of Neogene rocks in the fine gravel fraction (5-10 mm) of the upper subunit is negligible for other reasons.…”

Palaeogeographical significance of the Eemian biogenic sediments at the Bór site (Warta River valley, central Poland)

“…Flu vial sands and sands with grav els rep re sent ing be gin ning of the Mid dle Pol ish Complex lie above. Two ho ri zons of the Mid dle Pol ish Com plex tills were found (Czubla et al, 2010). Out side the Adamów graben the tills are thick, and dom i nate the Qua ter nary se ries, while in the graben their thick ness de creases or they are com pletely eroded or/and sep a rated by glaciolacustrine de pos its of the KoŸmin gla cial lake and glaciofluvial sand and grav els (Fig.…”