Petromagnetism and palaeomagnetism of Quaternary loess-soil sediments of Vyazivok section (Dnieper Lowland)

Abstract

The results of petromagnetic and palaeomagnetic research of Vyazivok loess-paleosoil sequence (Dnieper Lowland) are presented. Variations of natural remanent magnetization and magnetic susceptibility are not correlated with lithology. The rocks are characterized by high stability to alternating magnetic field demagnetization and temperature demagnetization due to the presence of highly coercive magnetic mineral — hematite. The other ferromagnetic minerals (magnetite and maghemite) are also presented. The paramagnetic minerals have a significant influence to magnetization and strongly affect to hysteresis loop parameters and other magnetic properties of rocks. The characteristic components of magnetization are characterized by normal polarity of samples above 56.2 m depth within the lower part of Shyrokino soil horizon. At the bottom of the section all samples demonstrate the reverse polarity. We proved that the Matuyama—Brunhes inversion is correlated with this level. The position of Matuyama—Brunhes boundary in Roxolany and Vyazivok sections are controversial following the local stratigraphy schemes, which can be explained either by delay of «magnetic record» in soil or incorrect stratigraphic subdivision of section (probably Roxolany)