Geophysical Journal | 2015 volume 37 1

Paleomagnetic and rock magnetic study of Lower Devonian red beds from Podolia, SW Ukraine: remagnetization problems

© V. Bakhmutov, M. Jelenska, M. Kqdzialko-Hofmokl, I. Poliachenko, L. Konstantinenko, P. Ziolkowski, 2015

Paleomagnetic study of Lower Devonian sedimentary sequence in Podolia (SW Ukraine, along the Dniester River) represented by red beds of Dniestrovskaya series were carried out. Two components of NRM were revealed. First component recognized in almost all samples in diapason of unblocking temperature of 150-200 to 530-630 has SSW declination and negative inclination. Pole positions calculated from these direction (47S, 351,5E) lie in the Permian segment of APWP published by [Torsvik et al., 2012] for Baltica / Stable Europe. The best candidate for magnetic carrier of Permian remagnetization is secondary authigenic, pure hematite crystals residing in ferruginous cement of sandstones or in chlorite grains. In red beds the Permian component of NRM is of chemical origin. The second component was isolated at the end of thermal demagnetization path in diapason of unblocking temperature of 590-610 to 680-690. It has SW declination and positive inclination. Pole positions calculated from these direction (2,3S, 338,4E) lie close to Devonian segments of APWP. This component is characteristic of detritic grains of hematite. There are several facts supporting the hypothesis that this component is primary magnetization which recorded Devonian paleofield. New results are consistent with previously obtained in the area of paleomagnetic directions of red beds [Smethurst, Khramov, 1992] and gray-colored deposits of Lower Devonian.

Key words: devonian, southwestern Ukraine, red beds, paleomagnetic data, magnetic properties.

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