HR: 1400h
AN: V43A-08    [Abstracts]
TI: Granulometric, Modal, SEM and EPMA Analyses of ashes and SO2 Emissions from Popocatépetl volcano (Mexico): Coupling Data for Identification of Eruptive Processes
AU: * Linares-Lopez, C
EM: linaresc@geofisica.unam.mx
AF: Laboratorio Universitario de Petrologia, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Coyoacan, Mexico, DR 04510, Mexico
AU: Reyes-Salas, M
EM: adelars@servidor.unam.mx
AF: Laboratorio Universitario de Petrologia, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Coyoacan, Mexico, DR 04510, Mexico
AU: Delgado-Granados, H
EM: hugo@geofisica.unam.mx
AF: Laboratorio Universitario de Petrologia, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Coyoacan, Mexico, DR 04510, Mexico
AB: Popocatépetl has being erupting effusively and explosively for the last 12 years. During this time, ash samples have been collected at several sites around the volcano, depending on the dispersion axis of the volcanic cloud. Granulometric and modal analyses have been carried out on these samples and the results allowed the construction of a data set that reveals several processes that occur before their settling at different distances from the volcano during the explosive events. We have separated the samples selecting those that come from locations at comparable distances from the vent (<47Km).This distinction allows choosing better the working fractions. After modal analyses of the samples, the most abundant fraction has been used in order to carry out SEM imaging EDS and EPMA analytical work. Starting with analyses for pumices, glasses and olivine crystals from samples obtained since 1995 (2 samples per year at least), several processes come clearer. Pumices are less abundant in comparison with other components (such as lithic fragments, crystals, and glass shards). They show little development of vesicles except for particular dates. Glass shards increased their content in the sample of the year 2000. The olivine crystals have changed their composition along the eruptive period. All this information together with SO2 emission rates are used to document processes associated to degassing processes, periods for entrance of new batches of magma, and crystal segregation.
DE: 8404 Volcanoclastic deposits
DE: 8419 Volcano monitoring (7280)
DE: 8428 Explosive volcanism
DE: 8488 Volcanic hazards and risks
DE: 8494 Instruments and techniques
SC: Volcanology, Geochemistry, and Petrology [V]
MN: 2007 Joint Assembly