Deposit temperature of pyroclastic density currents emplaced during El Chichon 1982 and Colima 1913 eruptions

New data on the pyroclastic density current (PDC) deposit temperature (Tdep) are provided for two prominent eruptions of Mexican volcanoes of the twentieth century: the 1982 eruption of El Chicho´n and the 1913 eruption of Colima. In spite of similar lithofacies, magma composition and pre-eruptive conditions, the Tdep of the PDCs from the 1982 (El Chicho´n) and 1913 (Colima) eruptions differ significantly, with intervals of Tdep of 360–420 8C and 250–330 8C, respectively. These new data emphasize that a full understanding of the physical mechanisms responsible for equilibrium temperature attainment within a pyroclastic deposit has not yet been realized. The Tdep measured for El Chicho´n PDC deposits confirm the preliminary data published elsewhere, while Colima magnetic temperatures provide different values to those published previously.