Abstract The temperature of the deposits ( T dep ) 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 AD-Pompeii and 472 AD-Pollena eruptions. The T dep mainly fall in the range 270–370 °C and no significant correlation is evidenced between sedimentological features, eruptive and depositional processes and the final T dep . 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.

Abstract New data on the pyroclastic density current (PDC) deposit temperature ( T dep ) are provided for two prominent eruptions of Mexican volcanoes of the twentieth century: the 1982 eruption of El Chichón and the 1913 eruption of Colima. In spite of similar lithofacies, magma composition and pre-eruptive conditions, the T dep of the PDCs from the 1982 (El Chichón) and 1913 (Colima) eruptions differ significantly, with intervals of T dep of 360–420 °C and 250–330 °C, 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 T dep measured for El Chichón PDC deposits confirm the preliminary data published elsewhere, while Colima magnetic temperatures provide different values to those published previously. Supplementary material: T dep measurements for the different sites at El Chichon volcano and Colima volcano are available at: http://www.geolsoc.org.uk/SUP18695 .

Abstract The magnetic fabric of the Pliocene Kızılkaya ignimbrite in the Central Anatolian Volcanic Province has been investigated by anisotropy of magnetic susceptibility (AMS) and isothermal remanent magnetization (AIRM). Seven sections were sampled at various stratigraphic heights within the devitrified portion of the ignimbrite. The magnetic mineralogy is complex: titanomagnetite occurs as magmatic grains, and as inclusions in other phenocryst and glass shards; an oxidized phase and hematite occur in deposit levels affected by alteration processes. The disturbance produced by lithic and pumice clasts has been reduced by discarding the specimens that deviate more than ±1σ from the site mean value of the density. The AMS fabric varies along each individual section. Neither the AMS magnetic lineation nor the magnetic foliation plunge clearly define a common area as the vent location. The AIRM fabric of low-coercivity minerals, mainly represented by free titanomagnetite grains of magmatic origin, is consistent between sites and the inferred flow directions converge on a region near Derinkuyu, in the Nevsehir plateau, previously reported as the Kızılkaya ignimbrite source area. This study shows that systematic use of the remanent fabric improves the results given by AMS and aids the identification of the primary magnetic fabric related to the ignimbrite emplacement dynamics.