Fractional degassing of S, Cl and F from basalt magma in the Bárðarbunga rift zone, Iceland

Sigmarsson, Olgeir; Moune, Séverine; Gauthier, Pierre‐Jean

doi:10.1007/s00445-020-01391-7

Cited by 9 publications

(23 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…9b). First, the early degassing of sulphur described above will decrease the S/Cl ratio of the remaining undegassed volatiles 67 . The higher solubility of Cl in silicate melts means that Cl is more likely to degas during lava flow emplacement than at the vent, while the majority of the sulphur will degas at the vent 83,84 .…”

Section: Resultsmentioning

confidence: 99%

“…Further, our results highlight the unique metal signature of lava-seawater interaction plumes, which would have occurred throughout Earth's history during: oceanic plateau basalt eruptions [28][29][30][31][32][33][34][35] , continental flood basalt eruptions that reached coastlines 26,27 and the early stages of continental rifting 34,35 . Degassing of trace metals from late-stage lava flows at chlorinerich ocean entries, where melts are enriched in Cl over S due to fractional degassing [66][67][68][69] , produces a fundamentally different fingerprint of trace metals to magmatic plumes. Our results suggest that laze plumes have the potential to produce higher emission rates of Cu than even large magmatic plumes.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Volatile metal emissions from volcanic degassing and lava–seawater interactions at Kīlauea Volcano, Hawai’i

Mason

Wieser

Liu

et al. 2021

Commun Earth Environ

View full text Add to dashboard Cite

Volcanoes represent one of the largest natural sources of metals to the Earth’s surface. Emissions of these metals can have important impacts on the biosphere as pollutants or nutrients. Here we use ground- and drone-based direct measurements to compare the gas and particulate chemistry of the magmatic and lava–seawater interaction (laze) plumes from the 2018 eruption of Kīlauea, Hawai’i. We find that the magmatic plume contains abundant volatile metals and metalloids whereas the laze plume is further enriched in copper and seawater components, like chlorine, with volatile metals also elevated above seawater concentrations. Speciation modelling of magmatic gas mixtures highlights the importance of the S2− ligand in highly volatile metal/metalloid degassing at the magmatic vent. In contrast, volatile metal enrichments in the laze plume can be explained by affinity for chloride complexation during late-stage degassing of distal lavas, which is potentially facilitated by the HCl gas formed as seawater boils.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Volatile metal emissions from volcanic degassing and lava–seawater interactions at Kīlauea Volcano, Hawai’i

Mason

Wieser

Liu

et al. 2021

Commun Earth Environ

View full text Add to dashboard Cite

show abstract

“…At higher pressures (1 bar) the dominant S-speciation changes to S2 becoming subordinate relative to H2S and COS. As such, the amount of degassing expected from our elements of interest is S > Cl > F > Zn, in agreement with the trend of Ustunisik et al (2015). Sulfur is likely the most readily degassed volatile followed by Cl where the vapor-melt partition coefficient (2.2 to 13-85) is influenced by the abundance of H2O and S in the melt whereas F is unaffected (1.8) (Sigmarsson et al, 2020). Sulfur in particular is recognized to efficiently degas from basaltic melts, with some terrestrial lavas having lost up to 94% of their initial sulfur following exhumation and solidification (Bali et al, 2018; , 2016).…”

Section: Discussionmentioning

confidence: 99%

“…In contrast, F and Cl are minimally lost owing to their high solubilities (several wt%) in H2O-poor basaltic melts (Webster et al, 1999). Low Cl vapor-melt partition coefficients may also reflect the decreased role of carrier gas phases such as H2O and SO2 which facilitate the formation of HCl and S-Cl ligands (Sigmarsson et al, 2020;Zolotov and Matsui, 2002). The affinity for Zn in the vapor phase is more difficult to constrain, although the high Zn abundance on the coatings of volcanic glass beads is necessarily explained by Zn vaporization during lunar volcanism (Hauri et al, 2015;Ma and Liu, 2019).…”

Section: Discussionmentioning

confidence: 99%

The Zn, S, and Cl isotope compositions of mare basalts: Implications for the effects of eruption style and pressure on volatile element stable isotope fractionation on the Moon

Gargano

Dottin

Hopkins

et al. 2022

American Mineralogist

View full text Add to dashboard Cite

We compare the stable isotope compositions of Zn, S, and Cl for Apollo mare basalts to better constrain the sources and timescales of lunar volatile loss. Mare basalts have broadly elevated yet limited ranges in δ66Zn, δ34S, and δ37ClSBC+WSC values of 1.27 ± 0.71, 0.55 ± 0.18, and 4.1 ± 4.0‰, respectively, compared to the silicate Earth at 0.15, –1.28, and 0‰, respectively. We find that the Zn, S, and Cl isotope compositions are similar between the low- and high-Ti mare basalts, providing evidence of a geochemical signature in the mare basalt source region that is inherited from lunar formation and magma ocean crystallization. The uniformity of these compositions implies mixing following mantle overturn, as well as minimal changes associated with subsequent mare magmatism. Degassing of mare magmas and lavas did not contribute to the large variations in Zn, S, and Cl isotope compositions found in some lunar materials (i.e., 15‰ in δ66Zn, 60‰ in δ34S, and 30‰ in δ37Cl). This reflects magma sources that experienced minimal volatile loss due to high confining pressures that generally exceeded their equilibrium saturation pressures. Alternatively, these data indicate effective isotopic fractionation factors were near unity. Our observations of S isotope compositions in mare basalts contrast to those for picritic glasses (Saal and Hauri 2021), which vary widely in S isotope compositions from –14.0 to 1.3‰, explained by extensive degassing of picritic magmas under high-P/PSat values (>0.9) during pyroclastic eruptions. The difference in the isotope compositions of picritic glass beads and mare basalts may result from differences in effusive (mare) and explosive (picritic) eruption styles, wherein the high-gas contents necessary for magma fragmentation would result in large effective isotopic fractionation factors during degassing of picritic magmas. Additionally, in highly vesiculated basalts, the δ34S and δ37Cl values of apatite grains are higher and more variable than the corresponding bulk-rock values. The large isotopic range in the vesiculated samples is explained by late-stage low-pressure “vacuum” degassing (P/PSat ~ 0) of mare lavas wherein vesicle formation and apatite crystallization took place post-eruption. Bulk-rock mare basalts were seemingly unaffected by vacuum degassing. Degassing of mare lavas only became important in the final stages of crystallization recorded in apatite—potentially facilitated by cracks/fractures in the crystallizing flow. We conclude that samples with wide-ranging volatile element isotope compositions are likely explained by localized processes, which do not represent the bulk Moon.

show abstract

“…The strong affinity of the degassed elements for chloride speciation, either at or above magmatic plume chloride concentrations, suggests that their degassing and/or detection at the ocean entry might be facilitated by the presence of elevated chloride.The availability of Cl at the ocean entry is likely to be higher than that at Fissure 8 for two reasons. Firstly, fractional degassing of lavas between the source and the distal lava flows will decrease the S/Cl ratio of the remaining undegassed volatiles (by Rayleigh distillation)63 . For example, during the later stages of degassing of the 2014-15 Holuhraun eruption, S/Cl ratios in emissions were ~50 times lower than measured in the syn-eruptive plume.…”

mentioning

confidence: 99%

Volatile metal emissions from volcanic degassing and lava-seawater interactions at Kīlauea Volcano, Hawai’i

Mason

Wieser²,

Liu³

et al. 2020

Preprint

View full text Add to dashboard Cite

Volcanoes represent one of the largest natural sources of metals to Earth’s surface. Emissions of these pollutants and/or nutrients have important implications for the biosphere. We compare gas and particulate chemistry, including metals, of the substantial magmatic (≥200 kt/day SO2) and lava-seawater interaction (laze) plumes from the 2018 eruption of Kīlauea, Hawai’i. The magmatic plume contains abundant volatile chalcophile metals (e.g. Se), whereas the laze is enriched in seawater components (e.g. Cl), yet Cu concentrations are 105 times higher than seawater. High-temperature speciation modelling of magmatic gases at the lava-air interface emphasises chloride’s critical role in metal/metalloid complexation during degassing. In the laze, concentrations of moderately (Cu, Zn, Ag) to highly volatile (Bi, Cd) metals are elevated above seawater. These metals have an affinity for chloride and are derived from late-stage degassing of distal lavas, potentially facilitated by the HCl gas formed as seawater boils. Understanding these processes yields insights into the environmental impacts of volcanism in the present day and geological past.

show abstract

Fractional degassing of S, Cl and F from basalt magma in the Bárðarbunga rift zone, Iceland

Cited by 9 publications

References 35 publications

Volatile metal emissions from volcanic degassing and lava–seawater interactions at Kīlauea Volcano, Hawai’i

Volatile metal emissions from volcanic degassing and lava–seawater interactions at Kīlauea Volcano, Hawai’i

The Zn, S, and Cl isotope compositions of mare basalts: Implications for the effects of eruption style and pressure on volatile element stable isotope fractionation on the Moon

Volatile metal emissions from volcanic degassing and lava-seawater interactions at Kīlauea Volcano, Hawai’i

Contact Info

Product

Resources

About