Application of anisotropy of magnetic susceptibility (AMS) for the determination of paleo-wind directions and paleo-environment during the accumulation period of Bag Tephra, Hungary

Abstract

This study provides the first application of anisotropy of magnetic susceptibility (AMS) measurements for the study of Pleistocene-wind directions and the environment during the deposition of dust and lithifaction of loess in the Carpathian Basin. A total of 67 samples were taken from seven loess–paleosol outcrops to test this method on loess–paleosol sequences. The samples were collected from the loess overlying the Bag Tephra, a characteristic marker horizon of the middle Pleistocene age in the Hungarian loess sequences. Statistical analysis of AMS is a good tool to distinguish between redeposited and the undisturbed loess. The first measurements indicated a N/NE–S/SW direction dust transport. In two outcrops, when the principal susceptibilities were placed into a stereographic projection, the effect of local slope proved to be important in determining the magnetic fabric. The AMS results were completed by isothermal remanent magnetization (IRM) measurements to determine the main magnetic mineral components of the samples. The dominant magnetic mineral which determines the AMS character of the sample was magnetite (or maghemite).