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Composition-resolved size distributions of volcanic aerosols in the Mt. Etna plumes

Authors :
Claire J. Horwell
Andrew G. Allen
Tamsin A. Mather
R.S. Martin
David M. Pyle
E. P. W. Ward
Alessandro Aiuppa
M. R. Power
MARTIN RS
MATHER TA
PYLE DM
POWER M
ALLEN AG
AIUPPA A
HORWELL CJ
WARD EPW
Source :
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES. 113(D17)
Publication Year :
2008

Abstract

Particle size distributions for soluble and insoluble species in Mt. Etna's summit plumes were measured across an extended size range (10 nm < d < 100 μm) using a combination of techniques. Automated scanning electron microscopy (QEMSCAN) was used to chemically analyze many thousands of insoluble particles (collected on pumped filters) allowing the relationships between particle size, shape, and composition to be investigated. The size distribution of fine silicate particles (d < 10 μm) was found to be lognormal, consistent with formation by bursting of gas bubbles at the surface of the magma. The compositions of fine silicate particles were found to vary between magmatic and nearly pure silica; this is consistent with depletion of metal ions by reactions in the acidic environment of the gas plume and vent. Measurements of the size, shape and composition of fine silicate particles may potentially offer insights into preemission, synemission, and postemission processes. The mass flux of fine silicate particles from Mt. Etna released during noneruptive volcanic degassing in 2004 and 2005 was estimated to be ∼7000 kg d-1. Analysis of particles in the range 0.1 < d/μm < 100 by ion chromatography shows that there are persistent differences in the size distributions of sulfate aerosols between the two main summit plumes. Analysis of particles in the range 0.01 μm < d < 0.1 μm by scanning transmission electron microscopy (STEM) shows that there are significant levels of nanoparticles in the Mt. Etna plumes although their compositions remain uncertain. Copyright 2008 by the American Geophysical Union.

Details

Language :
English
ISSN :
2169897X
Volume :
113
Issue :
D17
Database :
OpenAIRE
Journal :
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
Accession number :
edsair.doi.dedup.....3c29cbfbb8d0a6c47ca225ad97b9f097