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Stratigraphy and conditions of accumulation of the Younger Loesses (Vistulian) in the Holy Cross Mountains area, Poland

Dzierżek Jan, Lindner Leszek

Studia Quaternaria

2020

Vol. 37, Nr 2

109--120

The paper presents results of studies focused on occurrence and correlation of four main horizons of Younger Loesses: Lowest Younger Loess (LMn – after Maruszczak, 2001), Lower Younger Loess (LMd), Middle Younger Loess (LMs), and Upper Younger Loess (LMg) recorded in five sections (Politów, Wąchock, Nietulisko Małe, Komorniki and Bodzechów) in the Holy Cross Mountains area. All analysed loesses were accumulated during the Vistulian Glaciation (Weichselian). The horizons were distinguished based on separating interstadial tundra soils, coupled with thermoluminescence dating, and correlated with marine oxygen-isotope stages MIS 5d−2. The Lowermost Younger Loess (LMn) covers the Nietulisko I soil complex (Jersak, 1973), developed on deposits of the Odranian Glaciation (MIS 6) and representing a forest soil of the Eemian Interglacial (MIS 5e) and the Brørup warming (MIS 5c). A thin horizon of the Oldest Younger Loess and a thin sandy horizon, both probably corresponding to the Herning cooling phase (MIS 5d) at the boundary with the Eemian Interglacial, were distinguished within this complex. Based on previously performed grain-size and heavy mineral analysis of the Upper Younger Loess (LMg) and a topographic position of the loesses in four loessy islands of diverse regional extent, accumulation of this loess in the Holy Cross Mountains area is found to have been stimulated by the western winds. The proposed model of loess accumulation takes into account the influence of the topography of the area and its geological structure.

The loess section in Wąchock as the key site of Vistulian loesses and palaeosols in the Holy Cross Mountains (Poland)

Dzierżek Jan, Lindner Leszek, Nawrocki Jerzy

Geological Quarterly

2020

Vol. 64, No. 2

252--262

The Wąchock section (N part of the Holy Cross Mountains) is bipartite, with a sub-loess lower part and a loess upper part. The sub-loess part lying on Lower Triassic sandstones includes fluvial, glacial and ice-dammed lake deposits, TL-dated at 352 ky BP to 157 ±23 ky BP. They represent the Mazovian (MIS 11) (Zbójnian?, MIS 9?) Interglacial and the Odranian Glaciation (MIS 6). The upper part comprises loesses intercalated with palaeosols, which reach a total thickness of 9 m and have TL ages at 148 ±23 ky BP to 15.8 ±8 ky BP. This part of the succession begins with horizon B of a brown soil from the Eemian Interglacial (MIS 5e) with an interstadial black soil from the oldest Vistulian (MIS 5c). Four younger loess horizons from the middle and younger Vistulian occur above; loesses with arctic and tundra palaeosols correspond to younger isotope stages (MIS 5b-MIS 2). The loess and palaeosol horizons distinguished in Wąchock were correlated with loess sections in Poland (Zwierzyniec and Polanów Samborzecki) and western Ukraine (Kolodiiv 3), showing large similitarities of both loesses and palaeosols. Due to this, the Wąchock site is proposed as a one of key sections for Vistulian loess sequences not only in the Holy Cross Mts. region but also in Central Europe. Palaeomagnetic studies of the Wąchock loesses have registerered palaeomagnetic inclinations with values lower than the average values expected in this locality (63°).