Stratigraphy, chemistry, and eruptive dynamics of the 12.4 ka plinian eruption of Apoyeque volcano, Managua, Nicaragua
Por:
Avellán D.R., Macías J.L., Sosa-Ceballos G., Velásquez G.
Publicada:
1 feb 2014
Categoría:
Geochemistry and Petrology
Resumen:
Apoyeque volcano, located 9 km northwest of Managua city, erupted explosively at 12.4 ka. The Plinian eruption deposited a widespread pumice fall deposit known as the Upper Apoyeque Tephra (UAq). The UAq is massive, reversely graded, and consists of white juvenile pumice (~78 vol.%), a variety of cognate lithics and accidental altered lithics. The whole-rock pumice composition is rhyodacitic (SiO2 = 66.9-68.5 wt.%) with a mineral paragenesis of plagioclase, orthopyroxene, clinopyroxene, amphibole, titanomagnetite, and ilmenite in a rhyolitic glass groundmass (SiO2 = 74.4 ± 0.6 wt.%). The deposit's dispersal axis is to the south, with the deposit covering a minimum area of 877 km2 within the 50 cm isopach and has a total volume of 3 km3 (dense rock equivalent, 1.15 km3). The eruption column reached a maximum height of ca.28 km. The eruption ejected a total mass of 3 × 1012 kg at an average rate of 2 × 108 kg/s, and based on available models, we infer duration of almost 4 h. Petrographic and geochemical characteristics suggest that the eruption was triggered by magma mixing. © 2014 Springer-Verlag Berlin Heidelberg.
Filiaciones:
Univ Nacl Autonoma Mexico, Unidad Michoacan, Inst Geofis, Morelia 58190, Michoacan, Mexico
Facultad de Ciencias e Ingeniería, Universidad Nacional Autónoma de Nicaragua, Managua, Nicaragua
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