Age and sedimentological features of fluvial series in the Toruń Basin and the Drwęca Valley (Poland)

Abstract

Abstract:The deposits of the Toruń Basin are dominated by a few-metre thick sand series which fill up buried valley-like depressions. In many cases they underlie the Weichselian till which builds up the ice marginal streamway (pradolina) terraces or they are exposed at the basin slopes. As the results of the geological and sedimentological studies, as well as of the dating of the deposits at the sites in the Toruń Basin indicate, the deposits include two fluvial series accumulated before the advancement of the Leszno Phase ice sheet, i.e. in Middle Weichselian and at the beginning of Late Weichselian. The oldest fluvial series connected with the Saalian Glaciation was found at the mouth section of the Drwęca Valley. The fluvial system of the Toruń Basin during Middle Weichselian and at the beginning of Late Weichselian developed in two phases of the sand-bed braided river. During the first one the river channel were dominated by large mid-riverbed sandbars, while during the second phase the water flow was smaller and, as a result, low transverse sandbars and two-dimensional dunes developed. Other active river channel also showed low-energy flows, more intensive meandering than in the case of the braided rivers, as well as sandy side-bars. Analysis of the rounding and frosting of the quartz grains indicate that the studied series of the Weichselian sandy deposits represent alluvia of a river which were fed from two diverse sources. The first one might have represented the alluvia of a warm river which transformed its load, while the other one might have mainly carried the underlying Quaternary deposits.

Upper Pleistocene palaeoenvironmental changes at the Zwierzyniec site, central Poland

“…Feld spars, however, are mostly of rounded out line, mean ing the whole ma te rial un der went ae olian trans for ma tion (cf. Weckwerth et al, 2011). The feld spar de ple tion in the sam ple from a depth of 6.7 m was likely over lap ping with the de te ri o ra tion of cli mate con di tions recorded in the up per part of the pro file.…”

“…Si multa neously, the abun dance of shiny (EM/EL+EL) quartz grains is at trib uted to flu vial en vi ron ments (Krinsley and Doornkamp, 1973), and such de pos its could be typ i cal of river floodplains (Marks et al, 2014). It is ac knowl edged that a rel a tively high (>5%) num ber of grains with well-rounded out lines ob served in the sed i ments re fer ei ther to the un der ly ing de pos its (Woronko, 2001) or re sults from the long-last ing flu vial cy cles (Weckwerth et al, 2011). Sim i larly, the high con tent of cracked grains (C) indi cates the post-sed i men tary weath er ing due to freeze-thaw (Woronko and Hoch, 2011;Woronko, 2012) and have been reported from the for mer periglacial ar eas in north east ern Po land (Woronko et al, 2013).…”

“…Weckwerth et al, 2011;Dzieduszyñska et al, 2014;Kaliñska-Nartiša and Nartišs, 2016a). Oth ers, in con trast, lack of suf fi cient in ves ti ga tion.…”

Heavy minerals as a tool to reconstruct river activity during the Weichselian glaciation (Toruń Basin, Poland)

“…Recognising one of these two types of river-discharge regimes in front of the ice sheet provides the possibility of identifying the sediments deposited within an ice-marginal valley during the Pleistocene (see Toucanne et al, 2009; Westaway & Bridgland, 2010;Weckwerth et al, 2011;Weckwerth, 2013). The present contribution is therefore aimed to relate the genesis of the various lithofacies of the channel environment during the Weichselian glaciation with the composition of the mineral assemblages in the fluvial deposits.…”

The relation between optical bleaching and sedimentological features of fluvial deposits in the Toruń Basin (Poland)

“…Nowe D¹bie flu vial suc ces sion was de posited in a low-gra di ent (0.0003-0.0007 m/m), sand-bed braided river, where aggradational forms de vel oped (sandflat braided river; Cant, 1978;Cant and Walker, 1978;Zieliñski 1992Zieliñski , 1993Sambrook Smith et al, 2006;Ashworth et al, 2011;Weckwerth et al, 2011). The sandy flu vial suc ces sion (unit N1) rep re sents two flu vial subenvironments: chan nel de pos its [lithofacies as soci a tions Sp (Sh, Sr, St) and Sp (Sl, Sr, St); OSL sam ples KO1, KO3 and KO4] and floodplain de pos its [lithofacies as so ci a tion Sr, Src, SFh; OSL sam ple KO2; Fig.…”