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

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.