Magnetic parameters and palaeoclimate: A case study of loess deposits of North-East of Iran

Abstract

Environmental magnetism techniques enable us to reconstruct paleoclimate conditions in some deposition such as losses. The  magnetic properties  of  minerals  are  used  as  proxies  for  environmental  changes. For this study, loess/paleosol sequence of Kolet section at Neka, north-east of Iran were magnetically investigated. We applied environmental magnetism methods, to reconstruct paleoclimate changes. We investigated relationship between paleoclimate changes and environmental magnetism proxies like magnetic susceptibility (?) variation. The laboratory techniques indicated the presence of main factor of magnetic property in loess/paleosol sequence, such as magnetite, maghemite and etc. We also estimated magnetically parameters (like SIRM, HIRM and etc.) to confirm concentrations of both aeolian and pedogenic particles versus variations of magnetic susceptibility enhancement. The ? values show prominent peaks for the three well developed soil and paleosol horizons, Recent Soil (S0), Upper Paleosol (S1) and Lower Paleosol (S2); which refer to warmer and wetter conditions. As result, we concluded that the increase/decreasing of magnetic susceptibility is coinciding with palaeosol/loess sequence, and probably with humid/arid conditions. Moreover, variations of magnetic susceptibility versus lithological column of Kolet section enabled us to recognize paleoclimatically periods known as interglacial/glacial cycles. The obtained  magnetic  data  indicate  that  during over  the  past  50  ka,  there  have  been  at  least  two glacial/interglacial periods and since last 20 ka, there was no main glaciation occurrence, in the study area.