BIO-STRATIGRAPHY AND MAGNETO-STRATIGRAPHY IN THE TIBER VALLEY REVISED

The stratigraphy of three sections of marine deposits in the Tiber val ley, north of Rome, was investigated in detail. Biostratigraphic inves tigation covered the Valle Ricca (Tini quarry), Fosso Liano and Lugnan o sections. The Valle Ricca and Lugnano sections show continuity in se dimentation from the latest Pliocene to Early Pleistocene. In the Foss o Liano section Upper Pliocene sediments are missing, as in other outc rops in central Italy, and the Lower Pleistocene deposits lie unconfor mably on the Middle Pliocene ones. Possible causes of these features a re discussed. Magnetostratigraphy and rock magnetism analyses were per formed only in the Valle Ricca section. The data shows that the previo usly recognised reversal around a volcanic level is the effect of stro ng changes in the magnetic mineralogy and it is not representative of true geomagnetic changes. (C) 1998 INQUA/Elsevier Science Ltd. All rig hts reserved.