PALEOMAGNETISMO NEI SEDIMENTI EMIPELAGICI TARDO-PLEISTOCENICI DEL MAR TIRRENO

Abstract

The magnetic properties of late Quaternary hemipelag­ic sediment from piston core BS77-15 taken in the Tyrrheni­an Sea were investigated and the results compared with paleoclimatic records. The magnetic mineralogy of the sedi­ment was studied and the magnetic carriers were identified by their spectra of coercivity and unblocking temperature. Investigations of rock magnetic parameters such as the Natur­al Remanent Magnetization (NRM), the low field magnetic susceptibility x, the frequency dependent susceptibility xFD, the acquisition of Anhysteretic Magnetization (ARM) and Isothermal Magnetization (IRM) and the Median Destruc­tive Field (MDF) have established the downcore variations in terms of magnetic mineralogy, grain size and coercivity in the sediments. The rock magnetic parameters were com­pared with an alternative climatic record from the same core based on the faunal association of planktonic foraminifera. A significant correlation was found between faunal climatic record and xFD. Together with the magnetic properties of the sediment this suggests that a paleoclimatic signal is record­ed by a fine-grained low-coercivity fraction of the magnetic minerals.