Paleopedology and magnetic properties of Sari loess-paleosol sequence in Caspian lowland, northern Iran

The objective of this study was to characterize the morphological and magnetic properties of Sari loess-paleosol section in northern Iran for paleopedologic and paleoenvironmental interpretation. The section consisted of a modern soil (MS) and three paleosols (PS1, PS2, PS3) separated by loess layers (LS1, LS2 and LS3). Based on particle size distribution, clay mineralogy, carbonates distribution and size of secondary carbonates, pedogenic development of the soils was in order of PS3>PS2>PS1=MS. Presence of redoximorphic features in PS3 was attributed to alternate stagnic saturation due to local water or high precipitation. Dominance of smectite and vermiculite as well as large carbonated dolls in PS3 indicated suitable environment and sufficient time for pedogenic development. Magnetic properties (chi lf and chi fd%) were distinctly higher in MS, PS1 and PS2 when compared to loess layers. The Lowest magnetic properties values were observed in PS3 which can be the result of ferrimagnetic minerals destruction under hydromorphic conditions. The highest Fed content occurred in PS3, however, low chi lf/Fe-d ratio indicated that majority of the iron minerals in PS3 are not magnetic. In conclusion, the particle size distribution, clay mineralogy and carbonates features were indicative of pedogenesis intensity, whereas, magnetic properties were useful to characterize the pedogenic environment.