The morphogenesis of erosional valleys in the slopes of the Drwęca valley and the properties of their colluvial infills

Abstract

The article characterises Late Glacial and Holocene deposits and provides a morphometric analysis of erosional and denudation valleys in the slope and terraces of the Drwęca Valley near Jajkowo village, a few kilometres east of Brodnica. A detailed field mapping was used to identify in detail two such forms within the western slope of the Drwęca Valley. Based on the results, it was found that the longitudinal profiles of these forms are not aligned (with an inclination of approximately 4˚). The slopes of valley I are asymmetrical, with the southern slope being milder than the northern exposure, which is not the case with form II. Form I is narrower and has a V-shaped cross profile, while II is wider and has a trough-shaped profile cross profile. The side valleys were initially cut by the flow of what were most probably meltwaters and precipitation water from the moraine plateau, then the erosion stopped and the valleys gradually filled and widened mainly as a result of rinsing and mass movements, which may have been increased by man. Currently, forestry use is significantly reducing the activity of slope processes and rinsing. The sediments that fill the bottoms of these forms are usually consist of silt or sandy lithofacies with massive, streaky or deformation horizons. They are characterised by a significant enrichment in organic matter which is typical for colluvial deposits of young glacial areas. The relatively high pH values result from the investigated erosional forms intersecting into sediments rich in calcium carbonate. Moreover, groundwater flowing from the moraine plateau may also be the source of basic components.

Sedimentological features and depositional conditions of accumulative fans in the lower Serteyka River valley, Western Russia

“…The above-mentioned methods have been successfully implemented to analyse the erosion and accumulation processes of slope sediments (e.g. Twardy 1995Twardy , 2000Twardy , 2003Stochlak 1996;Smolska 2003;, 2007Kittel 2014Kittel , 2016Majewski 2014Majewski , 2017Paluszkiewicz 2014;Ratajczak-Szczerba, Paluszkiewicz 2015;Piech et al 2018;Karasiewicz et al 2019;Ginter et al under review).…”

“…The so-formed covers were then cut open and blurred by the processes of linear erosion and surface runoff. Another important element was the runoff of water on the frozen ground, and then the erosion of the adjacent layer (Klatkowa 1965;Majewski 2008;Tylman 2011;Karasiewicz et al 2019). In turn, Panin et al (2011) believe that slope wash was the main process shaping the slopes during the decline of the last ice age.…”

“…Massive sands and sandy silts interpreted as colluvia (with a massive structure) could have arisen as a result of creeping (Majewski, Paluszkiewicz 2019). In turn, massive sands and silty sands (with an average grain diameter from ˗0.5 to 6.3 phi and with a poor and moderate sorting) could also arise as a result of flushing occurring in the Late Weichselian and the early Holocene (Karasiewicz et al 2019). Boulder levels are associated with gravitational movements within the slopes in the cold periods of these periods (Tylman 2011;Majewski 2014;Majewski, Paluszkiewicz 2019).…”

“…regression of ice cover, fluvial and slope activity), climatic fluctuations (e.g. changes in rainfall), vegetation or water conditions influence the formation and development of gullies (Table 1) (Klatkowa 1965;Twardy 1995Twardy , 2008Twardy , 2017Starkel 2005;Valentin et al 2005;Panin et al 2009Panin et al , 2011Dreibrodt et al 2010;Paluszkiewicz 2011;Jaworski 2018;Piech et al 2018;Karasiewicz et al 2019;Ginter et al 2020, under review). On the other hand, the anthropogenic factor is human activity in its broader understanding, e.g.…”

“…deforestation, agricultural activity, the causing of fires (Twardy 1995(Twardy , 2008Smolska 2005;Sidorchuk et al 2006;Dotterweich 2008;Rodzik et al 2008Rodzik et al , 2015Dotterweich et al 2012;Golosov et al 2017;Poesen 2018;Piech et al 2018Piech et al , 2020Ginter et al under review). Sinkiewicz 1989Sinkiewicz , 1998Teisseyre 1994;Stochlak 1996; Smolska 2003Smolska , 2005Smolska , 2008Twardy 1995Twardy , 2000Twardy , 2008Belyaev et al 2005;Mycielska-Dowgiałło, Ludwikowska-Kędzia 2011;Kittel 2014Kittel , 2016Ratajczak-Szczerba, Paluszkiewicz 2015;Piech et al 2018;Karasiewicz et al 2019;Szwarczewski et al 2020; under review soil erosion, linear erosion, slope erosion, rill wash, splash erosion, piping intense rains; lack of a dense plant cover; high slope; slope surface made of fine material formation of small size cuts (rills); slope denudation Sinkiewicz 1989Sinkiewicz , 1998Teisseyre 1994;Stochlak 1996; Smolska 2003Smolska , 2005Smolska , 2007Smolska , 2008…”