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Three‐dimensional investigation of volcanic textures by X‐ray microtomography and implications for conduit processes
Author(s) -
Polacci Margherita,
Baker Don R.,
Mancini Lucia,
Tromba Giuliana,
Zanini Franco
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl026241
Subject(s) - strombolian eruption , geology , explosive eruption , scoria , pyroclastic rock , pumice , volcano , petrology , mineralogy , geochemistry
Synchrotron X‐ray computed microtomography (μCT) was applied for the first time to clasts of pumice and scoria generated by active, explosive volcanoes characterized by a range of eruptive styles (mild Strombolian to Plinian) and magmatic composition (basaltic to trachytic). The obtained two‐dimensional (2D) tomographic images, corresponding to sample views at different rotation angles, were processed to reconstruct three‐dimensional (3D) volumes and then used to make 3D measurements of vesicularity, vesicle number density, volume and connectivity for quantitative characterization of the investigated tephras. The results indicate a positive correlation between vesicle number density and eruption intensity that is used to investigate modes of magma degassing in explosive eruptions. In addition, the vesicle geometry affecting the connected gas flow pathways in pyroclasts from Strombolian eruptions is determined and related to the known permeabilities. Implications on the dynamics of explosive eruptions is discussed and, ultimately, used to quantitatively discriminate between different eruptive styles.