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

Abstract

In the Serteyka River valley in western Russia, eight accumulative fans formed at the mouths of ravines were examined geologically and geomorphologically. The test samples were collected from individual geological drillings made with a manual probe, as well as from excavations in the central and distal zones of the fans. Using the Gradistat program, sedimentological indicators were calculated, i.e. mean grain diameter (MZ), standard deviation (sorting -σI), skewness (SkI) and kurtosis (KG),and then particle-size distribution frequency curves, cumulative curves and a Passega C/M diagram were drawn. It has been documented that the grain size of the fan sediments depends on the characteristics of the source material. Analysis of sedimentological indicators (mean grain diameter, sorting, skewness, kurtosis) showed the studied fans deposits to have a large variability of erosion and accumulation conditions. For the deposits of younger fans, the 2 nd system of the MZ-versus-σI relationship after Mycielska-Dowgiałło (1995) was distinguished, while for the older, the 2 nd , 3 rd and 4 th systems were recognised. The main process of grain transport within these forms was saltation. The ravines on the eastern slope of the Serteyka valley were most likely created in the periglacial period, while the gullies on the western side of the valley developed in the early modern period.

Natural and anthropogenic factors affecting intense slope processes in Eastern Europe during the Modern Period: Serteyka river valley, Russia

“…There is a noticeable increase in calcium carbonate and conductivity in this unit. The pH values are between 5.5 and 5.8 (Ginter et al, 2023; Piech, 2021; Piech et al, 2018).…”

“…Lower deluvium was formed during the mudflows in the form of tongues, they are formed during violent downpours when the source material is very fine (Piech, 2021; Piech et al, 2018; Twardy, 2008). Some of the sediments could also be formed during the spring thaws, where the material was deposited on the ice and snow covers (Ginter et al, 2023).…”

“…These samples are also included in fields VI and V of the type of deposit environments, which demonstrates a transport took place in conditions of low turbulence or of moderate turbulence (Szmańda, 2010).The material was transported in conditions of low and moderate turbulence, and a part of the material is defined as homogeneous with different graining (see Szmańda, 2010).The diagram M z /σ 1 (Fig. 4B, Piech, 2021) shows the system 4 according to Mycielska-Dowgiałło and Ludwikowska-Kędzia (2011), which is characteristic, among others, for overbank-pool deposits. Looking at the results of sedimentological analysis, it can be concluded that during the accumulation of these sediments, two main processes operated: fluvial and slope processes, which intertwined and overlapped each other.…”

“…stands out from the rest, that is, it is close to the N-O segment (transport of grains via rolling) and is in field I (traction deposition with a small proportion of suspension predominates here) (Szmańda, 2010(Szmańda, , 2011.In the relationships of sedimentological indicators, it is impossible to unambiguously assign to the obtained results any system (according to Mycielska-Dowgiałło and Ludwikowska-Kędzia, 2011), because in the diagrams the samples from this layer take the form of a rather dense cloud of points. Middle deluvium was accumulated as a result of surface-flow during intense agrotechnical activities (Ginter et al, 2023;Piech, 2021).…”

“…Such studies were carried out, among others, in Poland (Dotterweich et al, 2012; Jaworski, 2018; Karasiewicz et al, 2019; Kittel, 2014, 2015, 2016; Majewski, 2017; Paluszkiewicz, 2011; Smolska, 2003, 2005; Szwarczewski et al, 2020; Twardy, 1995, 2008, 2011, 2017; Zgłobicki et al, 2014), in Germany (Dotterweich, 2005, 2008; Dreibrodt et al, 2010; Heine et al, 2005; Kleber and Terhorst, 2013; Lang, 2003; Zolitschka et al, 2003) or as well as in the Baltic States (e.g. Jarašiūnas et al, 2020; Soms, 2011) and also in Russia (Belyaev et al, 2020; Ginter et al 2023; Golosov, 2002; Golosov et al, 2017; Panin et al, 2009; Piech, 2021; Piech et al, 2018, 2020a, 2020b; Sidorchuk et al, 2006).…”