Magnetic properties and geochemistry of loess/paleosol sequences at Nowdeh section northeastern of Iran
Abstract. The loess-palesols sequences in the northeastern of Iran are high-resolution natural archive of climate and environmental change, providing evidence for the interaction between accumulation and erosion of aeolian and fluvial sediments during the Middle and Late Pleistocene. In this study, Azadshar (Nowdeh Loess Section) was selected to reconstruct Late Quaternary climate change. The Nowdeh loess/ paleosol sequences with 24 m thickness were sampled for magnetic and geochemical analysis. The section systematically and with high resolution (10 cm intervals) were sampled and totally 237 samples were taken. Magnetic susceptibility of all samples were measured in Environmental and Paleomagnteic laboratory based at Geological Survey of Iran, Tehran, Iran. The geochemical analysis of selected samples (peak of magnetic susceptibility) were included to assist the paleoclimatic interpretation of the magnetic signals. The result of magnetic susceptibility of Loess/paleosol deposits show low magnetic susceptibility values in cold and dry climate periods (Loess) and high magnetic susceptibility values in warm and humid climate periods (paleosoil). Comparison of magnetic and geochemical data show that the results of geochemical weathering ratio variations such as magnetic parameters variations are with magnetic susceptibility. High degree of coherency between the intensity of magnetic susceptibility and Rb/Sr, Mn/Ti, Zr/ Ti and Mn/ Sr ratio are confirmed.
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