Decompression experiments identify kinetic controls on explosive silicic eruptions

• Published in: Geophysical research letters Vol. 31; no. 8; pp. L08605 - n/a
• Main Authors: Mangan, M. T., Sisson, T. W., Hankins, W. B.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Geophysical Union 01.04.2004; Blackwell Publishing Ltd
• Subjects: Earth, ocean, space; Eruption mechanisms; Exact sciences and technology; Experimental mineralogy and petrology; Mineralogy and Petrology; Physics and chemistry of magma bodies; Volcanology; degassing; volcanic rocks; dacites; explosive eruptions; Supersaturation; igneous rocks; magmas; pressure; rhyolites; high temperature; intensity; nucleation; Dissolved gas; kinetics; melts
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2004GL019509

Eruption intensity is largely controlled by decompression‐induced release of water‐rich gas dissolved in magma. It is not simply the amount of gas that dictates how forcefully magma is propelled upwards during an eruption, but also the rate of degassing, which is partly a function of the supersaturation pressure (ΔPcritical) triggering gas bubble nucleation. High temperature and pressure decompression experiments using rhyolite and dacite melt reveal compositionally‐dependent differences in the ΔPcritical of degassing that may explain why rhyolites have fueled some of the most explosive eruptions on record.