Reconstruction of Caspian Sea level changes using magnetic susceptibility during the last millennium

Abstract

Magnetic susceptibility is one of the most important methods for monitoring sediment composition during environmental studies. In this research, to reconstruct the Caspian Sea level changes, magnetic susceptibility variations were used during studies of five sedimentary cores (K1,K3,K5,K7,N1), collected from bottom sediments of Gorgan Bay. Samples were analyzed for grain size, total organic matter, carbonate content and magnetic susceptibility (MS). The results showed a close relationship between particle size distribution and MS magnitude due to variation in terrestrial influx, which is caused by sea-level fluctuations in different times. This process increases with particle size and magnitude of MS simultaneously with sea level fall and decreases during sea level rise. Moreover, no relationship between magnitude of MS and carbonate content was observed. Using magnetic susceptibility curves with other data, such as geological and historical, it can be concluded that these data are suitable for the reconstruction of marine environments, especially in the near shore coastal area.