PETROFYZIKÁLNÍ CHARAKTERISTIKA SPRAŠE A FOSILNÍ PŮDY V HLINÍKU U LITOVLE

• Published in: Geologické výzkumy na Moravě a ve Slezsku
• Main Authors: Šimíček, Daniel, Krulová, Vendula
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Masaryk University Press 2018
• Subjects: Arctic; Magnetic susceptibility; Tundra
• Online Access: http://dx.doi.org/10.5817/gvms2018-1-2-58; https://journals.muni.cz/gvms/article/viewFile/8571/10143; https://journals.muni.cz/gvms/article/viewFile/8571/10282

Loess-paleosol sequences are an important source of terrestrial paleoclimatic proxy-data. Quaternary loess and loess loam cover the most of surface of the Upper Moravian Basin. Samples from loess-paleosol sequence in vicinity of Litovel town were studied using magnetic susceptibility, spectrophotometry and laser granulometry. Obtained petrophysical data were compared with detailed lithological description of section and geochemical characteristics determined by ED-XRF method. The results contribute to interpretation of paleoclimate in the Upper Moravian Basin during the last glacial.Section with total thickness of about 5 m is formed by loess in its upper part. This layer covers several soil horizons. It is most probably youngest loess deposit formed during the last glacial maximum. Petrophysical and geochemical data and comparison with nearby sites indicate relatively humid cold tundra conditions with bush-steppe vegetation during deposition of loess. Lithological features, position below youngest loess deposit and petrophysical and geochemical data allow interpretation of soil horizons as PK I. Low values of magnetic susceptibility indicate formation of soil in arctic interstadial conditions with higher humidity compared to interstadial average. Values of magnetic susceptibility of PK I are equal or even lower than in overlaying loess which doesn´t correspond with usual behaviour of magnetic susceptibility in loess-paleosol sequences in the Czech Republic. It could be explained by formation of soil horizons in cold interstadial climate (low production of oxi/hydroxide of Fe) supplemented by increased humidity and hence, intensive illimerization process (clay migration and Fe-minerals depletion).