What does magnetic susceptibility indicate about paleoclimate?

Answer 1

Detailed rock magnetic investigations and X-ray diffraction (XRD) were carried out on loess-paleosol sequences of the last interglacial-glacial at Znojmo section in Czech Republic. The results indicate that pedogenesis causes susceptibility enhancement in the paleosols, which is similar to that observed in the Chinese Loess Plateau. κ-T curves, IRM, and XRD show that magnetite is the dominant magnetic mineral in the loess-paleosol sequences at the Znojmo section, while maghemite, hematite, and pyrite/pyrrhotite are minor minerals. Measurements of anisotropy of magnetic susceptibility (AMS) indicate that the magnetic lineation is smaller than the foliation. The susceptibility ellipsoids are oblate and the directions of the maximum principal axes (Κmax) are distributed randomly, and cannot be used to determine the paleo-wind direction. Loess and paleosol sequences in the Czech Republic mainly occur in Bohemia and Moravia.

Although geological surveys of these wind-blown sediments can be traced to the 19th century, multiple investigations, such as paleoclimate, pollen and faunal analysis, chronology, and Archaeology etc., have recently been carried out to understand the formation and evolution of the aeolian sediments in this area[1 5]. The rock-magnetic properties of aeolian sediments in Czech Republic and their environmental implications are, however, still not well understood, and thus the relationship between aeolian paleo-environmental records in Czech Republic and China is ambiguous. We present here the results of a rock magnetic and XRD study of loess-paleosol sequences at Znojmo (48 51 N, 16 04 E) in Czech Republic. This investigation shows the utility of applying what has been learned from Chinese loess and extracts some of the sedimentary environment and paleoclimate information preserved in these aeolian deposits.