Estudio de las propiedades magnéticas en las terrazas del río Tajo: implicaciones paleoambientales

Abstract

Soil profiles from 12 terraces of Plio-Pleistocene to Holocene age from the Tajo river in Central Spain were investigated on there rock magnetic properties. Systematic profiles were sampled in 0.1m intervals from 24 fresh trenches of 2.5m depth. The soil profiles consist of an upper eluvial horizon (A, E), a intermediate illuvial horizon (B), and sometimes a lower horizon (C). Low and high frequency susceptibility (x), saturation IRM (SIRM), and anhysteretic remanent magnetization (ARM) measurements were performed out. The differences between the stable values of horizon B and the high values of the horizons A and E increase with the age of the soils. Comparison of the mean values of the B horizons for each terrace show low % values for the Holocene and the Late Pleistocene, a strong % increase during the Middle Pleistocene, and again low values for the Pliocene and Early Pleistocene. Magnetic parameters of soils show the palaeoenvironmental changes during this period of time