Vapor segregation and loss in basaltic melts

Edmonds, Marie; Gerlach, Terrence M.

doi:10.1130/g23464a.1

Cited by 81 publications

(82 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since CO 2 is significantly less soluble in basaltic melts than H 2 O, S, and Cl, and thus deeply exsolved, it was concluded that the gas slugs feeding Strombolian explosions have a relatively deep provenance (0.8-2.7 km below the summit vents). This deep source area also supported the idea of a separate ascent of gas and melt in the shallow (less than 2.7 km) plumbing system, as also proposed for other basaltic systems (Edmonds and Gerlach, 2007). Our measurements here extend further the conclusions of Burton et al (2007b): the temporal variability of the composition of the bulk (quiescent) plume requires the existence of a complex degassing regime in which a separate gas ascent plays a key role (Pichavant et al, 2009).…”

Section: Discussionsupporting

confidence: 75%

“…The so-called "excess degassing" (Shinohara, 2008), the fact that basaltic volcanoes no doubt emit more gas than potentially contributed by erupted magma, implies an effective gas bubble-melt separation at some point during the ascent. However, while it is universally accepted that separate gas transfer exerts a key control on both quiescent (Burton et al, 2007a) and eruptive (Edmonds and Gerlach, 2007) degassing of basaltic volcanoes, the mechanisms (structural vs. fluid-dynamic control) and depths (shallow vs. deep) of such gas separation are still not entirely understood (Edmonds, 2008). …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A model of degassing for Stromboli volcano

Aiuppa¹,

Bertagnini²,

Métrich³

et al. 2010

Earth and Planetary Science Letters

153

137

View full text Add to dashboard Cite

A better understanding of degassing processes at open-vent basaltic volcanoes requires collection of new datasets of H 2 O-CO 2 -SO 2 volcanic gas plume compositions, which acquisition has long been hampered by technical limitations. Here, we use the MultiGAS technique to provide the best-documented record of gas plume discharges from Stromboli volcano to date. We show that Stromboli's gases are dominated by H 2 O (48-98 mol%; mean, 80%), and by CO 2 (2-50 mol%; mean, 17%) and SO 2 (0.2-14 mol%; mean, 3%). The significant temporal variability in our dataset reflects the dynamic nature of degassing process during Strombolian activity; which we explore by interpreting our gas measurements in tandem with the melt inclusion record of pre-eruptive dissolved volatile abundances, and with the results of an equilibrium saturation model. Comparison between natural (volcanic gas and melt inclusion) and modelled compositions is used to propose a degassing mechanism for Stromboli volcano, which suggests surface gas discharges are mixtures of CO 2 -rich gas bubbles supplied from the deep (N4 km) plumbing system, and gases released from degassing of dissolved volatiles in the magma filling the upper conduits. The proposed mixing mechanism offers a viable and general model to account for composition of gas discharges at all volcanoes for which petrologic evidence of CO 2 fluxing exists. A combined volcanic gas-melt inclusion-modelling approach, as used in this paper, provides key constraints on degassing processes, and should thus be pursued further.

show abstract

Section: Discussionsupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

A model of degassing for Stromboli volcano

Aiuppa¹,

Bertagnini²,

Métrich³

et al. 2010

Earth and Planetary Science Letters

153

137

View full text Add to dashboard Cite

show abstract

“…Variations in magma-gas supply rates, 27 degassing modes and the style of convection actually determine a wide range in lava lake 28 behaviour, from vigorous bubbling and overturn to quieter degassing and resurfacing, 29 interrupted or not by recurrent gas outbursts (e.g. Le Guern et al, 1979;Tazieff, 1994;30 Oppenheimer et al, 200430 Oppenheimer et al, , 2009, and to cyclic upheaval and drain back due to gas-piston 31 effects (Edmonds and Gerlach, 2007;Patrick et al, 2016). 32…”

Section: Introductionmentioning

confidence: 99%

Degassing dynamics of basaltic lava lake at a top-ranking volatile emitter: Ambrym volcano, Vanuatu arc

Allard

Burton

Sawyer

et al. 2016

Earth and Planetary Science Letters

View full text Add to dashboard Cite

Persistent lava lakes are rare on Earth and provide volcanologists with a remarkable opportunity to directly investigate magma dynamics and degassing at the open air. Ambrym volcano, in Vanuatu, is one of the very few basaltic arc volcanoes displaying such an activity and voluminous gas emission, but whose study has long remained hampered by challenging accessibility. Here we report the first high temporal resolution (every 5 sec) measurements of vigorous lava lake degassing inside its 300 m deep Benbow crater using OP-FTIR spectroscopy. Our results reveal a highly dynamic degassing pattern involving (i) recurrent (100-200 sec) short-period oscillations of the volcanic gas composition and temperature, correlating with pulsated gas emission and sourced in the upper part of the lava lake, (ii) a continuous long period (∼8 min) modulation probably due to the influx of fresh magma at the bottom of the lake, and (iii) discrete CO 2 spike events occurring in coincidence with the sequential bursting of meter-sized bubbles, which indicates the separate ascent of large gas bubbles or slugs in a feeder conduit with estimated diameter of 6±1 m. This complex degassing pattern, measured with unprecedented detail and involving both coupled and 2 decoupled magma-gas ascent over short time scales, markedly differs from that of quieter lava lakes at Erebus and Kilauea. It can be accounted for by a modest size of Benbow lava lake and its very high basalt supply rate (~20 m 3 s -1 ), favouring its rapid overturn and renewal. We verify a typical basaltic arc signature for Ambrym volcanic gas and, based on contemporaneous SO 2 flux measurements, we evaluate huge emission rates of 160

show abstract

“…Further theoretical calculations by Vergniolle and Jaupart (1990) were built upon that study. Edmonds and Gerlach (2007) provided the first strong empirical data to support slug-driven gas pistoning. They used Fourier transform infrared spectroscopy (FTIR) to study the composition of gases emitted from a single gas piston event within Pu'u 'Ō'ō crater and determined that the event involved CO 2 -rich gas that segregated at depth.…”

Section: New Insights On Gas Pistoningmentioning

confidence: 96%

“…Each cycle lasted for about 20 min. Two contrasting models explain this behavior: in one, gas accumulates beneath the surface crust and is periodically released (crust-controlled; Swanson et al 1979); in the other, discrete gas slugs rise periodically in the conduit and burst at the surface (slug-controlled; Jaupart and Vergniolle 1988;Edmonds and Gerlach 2007). In most scenarios, geologic observations and geophysical data are incapable of favoring one mechanism over the other (e.g., Marchetti and Harris 2008).…”

Section: Introductionmentioning

confidence: 97%

Cyclic spattering, seismic tremor, and surface fluctuation within a perched lava channel, Kīlauea Volcano

et al. 2011

View full text Add to dashboard Cite

In late 2007, a perched lava channel, built up to 45 m above the preexisting surface, developed during the ongoing eruption near Pu'u 'Ō'ō cone on Kīlauea Volcano's east rift zone. The lava channel was segmented into four pools extending over a total of 1.4 km. From late October to mid-December, a cyclic behavior, consisting of steady lava level rise terminated by vigorous spattering and an abrupt drop in lava level, was commonly observed in pool 1. We use geologic observations, video, time-lapse camera images, and seismicity to characterize and understand this cyclic behavior. Spattering episodes occurred at intervals of 40-100 min during peak activity and involved small (5-10-m-high) fountains limited to the margins of the pool. Most spattering episodes had fountains which migrated downchannel. Each spattering episode was associated with a rapid lava level drop of about 1 m, which was concurrent with a conspicuous cigar-shaped tremor burst with peak frequencies of 4-5 Hz. We interpret this cyclic behavior to be gas pistoning, and this is the first documented instance of gas pistoning in lava well away from the deeper conduit. Our observations and data indicate that the gas pistoning was driven by gas accumulation beneath the visco-elastic component of the surface crust, contrary to other studies which attribute similar behavior to the periodic rise of gas slugs. The gas piston events typically had a gas mass of about 2,500 kg (similar to the explosions at Stromboli), with gas accumulation and release rates of about 1.1 and 5.7 kg s −1 , respectively. The time-averaged gas output rate of the gas pistoning events accounted for about 1-2% of the total gas output rate of the east rift zone eruption.

show abstract

Vapor segregation and loss in basaltic melts

Cited by 81 publications

References 18 publications

A model of degassing for Stromboli volcano

A model of degassing for Stromboli volcano

Degassing dynamics of basaltic lava lake at a top-ranking volatile emitter: Ambrym volcano, Vanuatu arc

Cyclic spattering, seismic tremor, and surface fluctuation within a perched lava channel, Kīlauea Volcano

Contact Info

Product

Resources

About