Dynamics of the ca. 4965 yr C-14 BP "Ochre Pumice" Plinian eruption of Popocatepetl volcano, Mexico
Por:
Arana-Salinas, L, Siebe, C, Macias, JL
Publicada:
10 may 2010
Resumen:
The Ochre Pumice (OP) Plinian fallout was produced by Popocatepetl volcano in central Mexico, during a major Plinian eruption that occurred 4965+/-65(14)C yr BP (3700 BC) The OP is part of the Ochre Pumice Sequence (OPS), that consists of surge, fall, and pyroclastic flow deposits The OP Plinian fallout shows a bimodal gram size distribution with poor to moderate sorting that improves progressively towards the upper beds The juvenile component is mainly pumice (>83 wt.%), whereas the accidental components consist of igneous, sedimentary, and metamorphic clasts from the walls of the magma chamber and/or conduit The vesiculanty of the pumice decreases from bottom to top of the stratigraphic sequence while the crystal and glass contents increase This suggests increasing magma degassing prior and during the eruption The chemical composition of the pumice varies insignificantly, at the base it is less evolved (SiO2=61 wt.%) and it becomes slightly more silicic towards the top (SiO2=63 wt %)
Filiaciones:
Arana-Salinas, L:
Univ Nacl Autonoma Mexico, Dept Vulcanol, Inst Geofis, Mexico City 04510, DF, Mexico
Siebe, C:
Univ Nacl Autonoma Mexico, Dept Vulcanol, Inst Geofis, Mexico City 04510, DF, Mexico
Macias, JL:
Univ Nacl Autonoma Mexico, Dept Vulcanol, Inst Geofis, Mexico City 04510, DF, Mexico
|