Factors controlling sedimentation in the Toruń-Eberswalde ice-marginal valley during the Pomeranian phase of the Weichselian glaciation: an overview

Abstract

During the Pleistocene the Scandinavian ice sheet drained huge quantities of sediment-laden meltwaters. These meltwaters supplied ice-marginal valleys that formed parallel to the front of the ice sheet. Not without significance was the supply of ice-marginal valleys from extraglacial rivers in the south. Moreover, periglacial conditions during and after sedimentation in ice-marginal valleys, the morphology of valley bedrocks, and erosion of older sediments played important roles in the depositional scenarios, and in the mineralogical composition of the sediments. The mechanisms that controlled the supply and deposition in ice-marginal valleys were analysed on the basis of a Pleistocene ice-marginal valley that was supplied by northern and southern source areas in the immediate vicinity. Investigations were conducted in one of the largest ice-marginal valleys of the Polish-German lowlands, i.e., the Toruń-Eberswalde ice-marginal valley, in sandurs (Drawa and Gwda) supplied sediments and waters from the north into this valley, and on extraglacial river terraces (pre-Noteć and pre-Warta rivers), formed simultaneously with the sandurs and ice-marginal valley (Pomeranian phase of Weichselian glaciation) supplied sediments and waters from the south into this valley. A much debated question is how similar, or different, depositional processes and sediments were that contributed to the formation of the Toruń-Eberswalde ice-marginal valley, and whether or not it is possible to differentiate mostly rapidly aggraded sandur sediments from ice-marginal valley sediments. Another question addresses the contribution of extraglacial feeding of the Toruń-Eberswalde ice-marginal valley. These matters were addressed by a wide range of analyses: sediment texture and structure, architectural elements of sediments, frequency of sedimentary successions, heavy-mineral analysis (both transparent and opaque heavy minerals), analysis of rounding and frosting of quartz grains, and palaeohydrological calculations. Additionally, a statistical analysis was used. The specific depositional conditions of distribution of sediments in ice-marginal valley allow to distinguish new environment of ice-marginal valley braided river. The spectrum of depositional conditions in the Toruń-Eberswalde ice-marginal valley and their specific palaeohydraulic parameters allow to distinguish three coexisting zones in the ice-marginal valley braided-river system: (1) deep gravel-bed braided channel zone with extensive scours, (2) deep sand-bed braided channel zone with transverse bars, and (3) marginal sand-bed and gravel-bed braided channel zone with diamicton and breccia deposition, which were characterised in detail. Some of the results have been published previously, which is why they are discussed in the present paper within the context of new data.

Fluvial responses to the Weichselian ice sheet advances and retreats: implications for understanding river paleohydrology and pattern changes in Central Poland

“…1). During the Weichselian glaciation, this basin was fed by precipitation-dependent (periglacial) rivers flowing from the south, but just as well by streams flowing from the north that were fed by the meltwater from the ice sheet (Weckwerth 2013;Weckwerth and Chabowski 2013;Pisarska-Jamroży 2015;Pisarska-Jamroży et al 2015). The position and extent of the basin was determined by valleys and glacial basins which evolved before the Last Glacial Maximum (LGM), i.e.…”

“…Fluvial successions accumulated in the Toruń-Eberswalde ice-marginal valley (pradolina 3) during Pomeranian phase indicate braided river environment which varied under the terms of morphology and flow energy (Fig. 15;Weckwerth 2010Weckwerth , 2013Pisarska-Jamroży 2015).…”

“…In the case of the Toruń Basin during the Weichselian glaciation the river regime depended on the extent of the nearby southern sector of the Scandinavian ice sheet (Weckwerth 2010(Weckwerth , 2013Weckwerth and Chabowski 2013;Pisarska-Jamroży 2015;Pisarska-Jamroży et al 2015;Woronko et al 2015) as well as to semi-cyclic alternations of climatic cooling and warming (references in the previous paragraph).…”

“…Van Loon 1999, 2003;Blažauskas et al 2007;Pisarska-Jamroży 2015). These past studies, however, did not consider to analyse the river regimes and their hydraulic parameters, in addition to changes in the ice-sheet edge position, also changed coevally due to climate fluctuations in the case of fluvial successions which nowadays are buried under Weichselian tills in Poland (Krzyszkowski 1996;Wysota et al 1996;Zieliński and Goździk 2001;Wysota 2002;Molewski 2007;Zieliński 2007;Weckwerth 2011).…”

Aeolian processes records within last glacial limit are as based on the Płock Basin case (Central Poland)

“…The Płock Basin is a vast extension of the Vistula River valley, being the easternmost part of the Toruń-Eberswalde ice-marginal valley (Galon & Roszkówna, 1961;Kozarski, 1965;Skompski, 1969;Pisarska-Jamroży, 2015). The Płock Basin's origin is related to a paleo-ice stream (B 3 ), a branch of the Baltic paleo-ice stream (Punkari, 1997).…”