RADIOMETRIC AND TEPHROANALYSIS DATING OF RECENT IONIAN SEA CORES

An accurate dating of recent Ionian Sea sediment cores has been performed by the Pb-210 radiometric method and by a detailed tephroanalysis. The markers of the historical volcanic eruptions which occurred in the Campanian area (Vesuvius, Phlegrean Fields, Ischia) during the last two millennia have been identified along the cores. Among the others, the famous Plinian Vesuvius eruption of 79 AD, which buried the Roman town of Pompei, has been recognized. Direct Pb-210 dating is limited to the last two centuries. The tephroanalysis demonstrates that the sedimentation rate estimated by the Pb-210 method is correct and it is constant, at least for the last 2 ky. The presence of the Cs-137 peak due to the intense activity of nuclear-weapon testing in the atmosphere in 1963-64 AD assures that the top of the core is present and not disturbed. The high precision of the core dating allows to transform the depth scale into a time scale with an accuracy of approximately 1%. The analysis of several cores taken in the same area demonstrates that the results presented here are of general validity, at least in this region. The carbonatic mud deposited in the last millennia in the Gallipoli Terrace can be successfully utilized for investigating the environmental conditions in the recent past.