Rock magnetic and palaeomagnetic studies of loess-palaesol sections — Lower Palaeolithic sites within the Southern Bug Valley (Medzhybizh, Holovchyntsi)

Abstract

Combined rock magnetic and palaeomagnetic studies of loess-soil sections — Lower Paleolithic sites in the valley of the Southern Bug (Medzhybizh, Holovchintsi) — have been performed for the first time in order to determine the suitability of these objects for palaeomagnetic study and the establishment of magnetostratigraphic markers. Investigated sections by rock magnetic characteristics are closest to the sections of the Volynian Upland, and refer to the intermediate «Chinese» type of formation of magnetic properties, with an admixture of the «Alaskan» mechanism. These sections are characterized by a low concentration of ferrimagnetic material, the destruction of the primary sedimentary magnetic texture, which makes them unsuitable for qualitative magnetostratigraphic studies. According to the data of magnetic-mineralogical analysis, the samples are subdivided into three groups: the first group includes samples with new formation at 300 °C, which is associated with iron hydroxides or the presence of organic matter; in the second group, the thermomagnetic curves are not informative, which makes it difficult to determine the minerals-carriers; in some samples, the magnetization carrier is magnetite (with defects or finely dispersed). A zone of normal polarity, probably the Brunhes chron, has been reliably determined in the upper part (G-S7S1 soil) of the Holovchyntsi section. In the lower part of the M-S4 soil unit (MIS 11) at Medzhybizh, the Unnamed geomagnetic event at 430 ky has been detected. The paleomagnetic veracity of the remaining investigated layers is questioned. The analogies for the archaeological assemblages from the lower layers of Medzhybizh-A and Holovchintsi-1 are seen in archaic industries of mode 1, which in southeastern Europe are dated back from 800 ky and older. However, reliable data on the Matuyama—Brunhes boundary and, correspondingly, data on the >780 ky age of any layers with artifacts in the Medzhybizh and Holovchintsi sections were not obtained by the palaeomagnetic studies.

Significance of the Ukrainian loess-palaeosol sequences for Pleistocene climate reconstructions: rock magnetic, palaeosol and pollen proxies

“…The position of the MBB in the Ukrainian loess-palaeosol sequences was established, with a high level of confidence, within the Lower Shyrokyne ('sh 1b1 ') subunit, for instance, at Roksolany and Vyazivok [Hlavatskyi, Bakhmutov, 2020]. At Stari Kaydaky, the MBB has not been detected yet as the base of the present profile is located within the upper 'sh 3 ' subunit, which has normal polarity elsewhere in the Ukrainian loess sequences [Tretyak, Vigilyanskaya, 1994;Hlavatskyi, 2019;Hlavatskyi et al, 2021b]. In the Brunhes chron, no reversed polarity episodes were identified at Stari Kaydaky as well.…”

“…Loess distribution (facies): 1loess, >5 m; 2 -loess, <2 m; 3 -sandy loess; 4 -loess derivates; 5 -loess and loess derivates in fragmentary distribution; 6 -alluvial loess; 7 -aeolian sand; 8 -loess thickness not differentiated. Selected Ukrainian loess sections: 9 -in which the MBB was detected by co-authors of the present study [Bakhmutov, Hlavatskyi, 2014;Hlavatskyi et al, 2016b;Bakhmutov et al, 2017;Hlavatskyi, Bakhmutov, 2019, 2020; 10 -other loess sections, studied palaeomagnetically by [Hlavatskyi et al, 2016a[Hlavatskyi et al, , 2021bBakhmutov et al, 2017]; 11 -loess sections currently under investigation; 12 -promising research sites, declared within the framework of the Project. The extent of the penultimate glaciation according to [Ehlers et al, 2011].…”

Early–Middle Pleistocene Magnetostratigraphic and Rock Magnetic Records of the Dolynske Section (Lower Danube, Ukraine) and Their Application to the Correlation of Loess–Palaeosol Sequences in Eastern and South-Eastern Europe

“…In the Stari Kaydaky and Holovchyntsi sections, the S7S1 soil is not less than 2 m thick and has normal polarity [235,299]. At Vyazivok, the palaeosol is equally 2 m thick, showing a specific double magnetic susceptibility peak in its lower part, somewhat similar to the Lake Baikal climate record for two early MIS substages 17c-e (Figure 11).…”