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Heavy and light minerals as a tool for reconstructing depositional environments: an example from the Jałówka site (northern Podlasie region, NE Poland)

Woronko Barbara, Rychel Joanna, Karasiewicz Mirosław T., Ber Andrzej, Krzywicki Tomasz, Marks Leszek, Pochocka-Szwarc Katarzyna

Geologos

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2013

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Vol. 19, No. 1-2

47--66

EN

Part of northern Podlasie (NE Poland), shaped during the Wartanian stadial of the Odranian glaciation (Saalian), was situated in the periglacial zone during the Vistulian (Weichselian) glaciation. Both landforms and sediments were affected by the periglacial conditions. This is recorded at the Jałówka site, at the floor of a dry valley, where mineral deposits of 4.13 m thick, overlying organic deposits from the Eemian interglacial, were examined. These mineral deposits form four units, from bottom to top: a fluvial unit (I), a loess-like unit (II), a solifluction unit (III), and an aeolian unit with ice wedges (IV) on top of unit III. The heavy and light minerals were analysed, as well as the geochemistry, in order to find out about the parent material and to reconstruct the climatic conditions during deposition. The mineral analysis indicates that the Saalian till was predominantly derived from shallow-marine deposits; erosion accompanied by sorting of the heavy minerals took place on the basis of their mass and grain size. The original material of the till seems therefore to be sedimentary rocks from the eastern Central Baltic Basin. This material became strongly weathered under the periglacial conditions, resulting in the destruction of the quartz grains, as well as in leaching, leading to complete decalcification of the deposits. Aeolian activity resulted in infilling of ice wedges and the creation of thin layers. The intensity and the duration of these processes was limited, so that the effects of the aeolian abrasion are insignificant. Neither resulted the aeolian activity in significant reshaping of the landscape.

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Pleistocene evolution of fault-line scarps in the northern margin of the Krzeszowice Graben, south Poland

Pawelec H.

Studia Quaternaria

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2007

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Vol. 24

29-35

EN

The paper aims at reconstructing Pleistocene slope processes and transformation of tectonic relief in two sections across the northern margin of the Krzeszowice Graben. The investigations are based on the analysis of deposits present on the slopes of fault-line scarps. The lithology and stratigraphy of these deposits was reconstructed based on analysis of outcrops and boreholes. Detailed lithological logs were prepared, along with grain size analyses, and determination of CaCO3, Fe2O3 and Corg contents in fine-grained sediments. The studied fault-line scarps were transformed by Pleistocene denudation. The type and intensity of these processes were different in the sections studied. In the Będkowice area, accumulation prevailed; the fault-line scarp became covered with sediments. In the Karniowice area, in turn, periglacial processes caused degradation of the fault-controlled slope. In the lower part of the fault-line scarp, the intensity of degradation processes was limited by repeated presence of sediment cover which preserved the substratum. Differences in the intensity and type of Pleistocene denudation can be explained by different heights of fault-line scarps, controlled by tectonic structure and neotectonic movements.

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Record and palaeogeographical implications of Pleistocene periglacial processes in the Drohiczyn Plateau, Podlasie Lowland (Eastern Poland)

Dzierżek J., Stańczuk D.

Geological Quarterly

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2006

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Vol. 50, No. 2

219-228

EN

The paper describes 51 ice-wedge casts from Wierzchuca Nagórna village near Drohiczyn town in the Podlasie Lowland in Eastern Poland. The structures are preserved in a till of theWartanian Glaciation. In the exposure the mean distance between them is 1.7 m; their mean length is 1 m, and their width ranges within 0.2–0.5 m. Most of the structures are typically wedge-shaped, although in some cases less regular pockets or veins are also observed. Some of the casts display a complex origin. They are filledmostly by fine-grained sand, in the lower parts with wind-corroded grains, as well as by sand with gravel from the overlying deposits. Near the ice-wedge casts, traces of frost swelling, uplift and sorting in permafrost conditions, as well as of an active layer are preserved. The thickness of the permafrost active layer, as preserved, is about 0.5–0.7 m. The formation of ice-wedges reflects periglacial conditions during the Vistulian (Weichselian) Glaciation. Three palaeogeographical alternatives are discussed. Probably, the lack of traces of periglacial activity from the Wartanian Glaciation is a result of plateau denudation. The range of this denudation has also been estimated.