2.1. Study area
The study area is the Nałęczów Plateau (East Poland) which covers 49608
ha (Figure 1).
The area is covered by loess patches which were mainly deposited during
the Vistulian Glaciation ( ca. 50 000 BP to 15 000/12 000 BP). These
loess patches are separated by river valleys where the loess cover is
absent (Maruszczak, 1991). The thickness of the loess reaches values of
10 to 20 m in the eastern part and up to 30 m in the western part of the
region (Harasimiuk, 1987).
Peat with a mean thickness of 3 m, covered by alluvial soils with a mean
thickness of 2.3 m, is found in the river valleys of the study area
(e.g. Bałaga & Maruszczak, 1981; Urban & Mikosz, 1996; Superson et
al., 2003, 2016).
The loess belt covers a Pleistocene sediment complex made up of
glacigenic deposits (glacial tills, sands and gravels, clayey loams,
clays) from the Odranian (Saale 1) and the Sanian (Elsterian) Glaciation
(Harasimiuk & Henkiel, 1978; Pożaryski et al., 1994). The bedrock of
the Nałęczów Plateau consists of Upper Maastrichtian (opoka, marly
opoka, marl) and Palaeogene (limestone, gaize and carbonate sandstone)
rocks (Pożaryska, 1967; Harasimiuk, 1980).
Vast surfaces of this loess plateau have CDs that are a typical element
of the landscape of the Nałęczów Plateau (Figure 1). CDs are shallow and
barely visible in loess landscape micro landforms, infilled by
soil-sediment sequences (Figure 2). Moreover, the Nałęczów Plateau is
dissected by main river valleys (Bystra, Ciemięga) and also small river
valleys (Grodarz, Czechówka) as well as many erosion-denudation valleys
and gully systems (Figure 1). The average density of the gully network
is 2.48-10 km per km2 in the western part of the
region, while in the eastern part it does not exceed 2 km per
km2 (Gawrysiak & Harasimiuk, 2012). The relative
heights in the region reach 40–50 m and maximally 90 m in the western
part of the region.
The loess of the Nałęczów Plateau is overlain by Luvisols in different
stages of erosion, Colluvisols in CDs and dry valley bottoms as well as
Fluvisols in valley bottoms.