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oa Extremely Low Magnetic Susceptibility in the Lubny (S5, Mis 13) Pedocomplex at the Type Locality Vyazivok (Central Ukrainian Loess Belt)
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, International Conference of Young Professionals «GeoTerrace-2023», Oct 2023, Volume 2023, p.1 - 5
Abstract
The type locality of the Lubny soil unit (S5; correlative of MIS 13) in the Quaternary stratigraphical framework of Ukraine (Veklich et al., 1993) is established at the Vyazivok site (the Poltava district). This is the only one pedocomplex in this loess-palaeosol succession, which has very low magnetic susceptibility values. The Lubny unit has been studied by rock magnetic methods in two excavations, where it is represented by three soils. From bottom to the top, they are Gleyic Luvisol (lb1b1), Gleyic Chernozem(lb1b2), and Gleyic Cambisol (lb3). Thus, all of them have hydromorphic features. According to hysteresis loop and χ(T) measurements of the sample from the A horizon of the Gleyic Chernozem lb1b2, a soft magnetic mineral (magnetite with a possible addition of maghaemite) was recognized. The frequency dependent magnetic susceptibility (χfd%) in the Lubny soils is close to 0%, which indicate an absence of superparamagnetic particles of the magnetite. The occurrence of low susceptibility values in the Lubny soils have been caused by a waterlogging which led to transformation of ferromagnetic minerals under hydromorphic processes. A similar pattern was observed in the Hungarian loess sequence, where the S5 palaeosol (correlative of MIS 13) has the same palaeopedological features, including gleying, as well as extremely low magnetic susceptibility values. This fact proves the existence of similar climatic conditions during the MIS 13 at least in the Dnipro Lowland and Pannonian Basin.