Temperatures of the pyroclastic density currents deposits emplaced in the last 22 kyr at Somma-Vesuvius (Italy)

The temperature of the deposits (Tdep) emplaced by the pyroclastic density current (PDC) generated by the seven major explosive eruptions from Somma–Vesuvius during the last 22 kyr were investigated using the thermal remanent magnetization (TRM) of lithic clasts embedded within the deposits. New data are presented for the Pomici di Base, Greenish Pumice, Mercato and 1631 AD deposits and compared to the literature data from the Avellino, 79 ADPompeii and 472 AD-Pollena eruptions. The Tdep mainly fall in the range 270–370 8C and no significant correlation is evidenced between sedimentological features, eruptive and depositional processes and the final Tdep. The admixture of ambient air during the run-out appears the most effective process to cool the temperature of the ash and gases of the PDC, and is therefore the main factor affecting the deposit temperature.