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Volcán Popocatépetl, Mexico. Petrology, magma mixing, and immediate sources of volatiles for the 1994- Present eruption

Journal of Petrology
By: , , and 
https://doi.org/10.1093/petrology/egi058

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Abstract

Volcán Popocatépetl has been the site of voluminous degassing accompanied by minor eruptive activity from late 1994 until the time of writing (August 2002). This contribution presents petrological investigations of magma erupted in 1997 and 1998, including major-element and volatile (S, Cl, F, and H2O) data from glass inclusions and matrix glasses. Magma erupted from Popocatépetl is a mixture of dacite (65 wt % SiO2, two-pyroxenes + plagioclase + Fe–Ti oxides + apatite, ∼3 wt % H2O, P = 1·5 kbar, fO2 = ΔNNO + 0·5 log units) and basaltic andesite (53 wt % SiO2, olivine + two-pyroxenes, ∼3 wt % H2O, P = 1–4 kbar). Magma mixed at 4–6 km depth in proportions between 45:55 and 85:15 wt % silicic:mafic magma. The pre-eruptive volatile content of the basaltic andesite is 1980 ppm S, 1060 ppm Cl, 950 ppm F, and 3·3 wt % H2O. The pre-eruptive volatile content of the dacite is 130 ± 50 ppm S, 880 ± 70 ppm Cl, 570 ± 100 ppm F, and 2·9 ± 0·2 wt % H2O. Degassing from 0·031 km3 of erupted magma accounts for only 0·7 wt % of the observed SO2 emission. Circulation of magma in the volcanic conduit in the presence of a modest bubble phase is a possible mechanism to explain the high rates of degassing and limited magma production at Popocatépetl.

Publication type Article
Publication Subtype Journal Article
Title Volcán Popocatépetl, Mexico. Petrology, magma mixing, and immediate sources of volatiles for the 1994- Present eruption
Series title Journal of Petrology
DOI 10.1093/petrology/egi058
Volume 46
Issue 11
Year Published 2005
Language English
Publisher Oxford Journals
Contributing office(s) Volcano Hazards Program
Description 30 p.
First page 2337
Last page 2366
Online Only (Y/N) N
Additional Online Files (Y/N) N
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