SO2 sequestration in large volcanic eruptions: High-temperature scavenging by tephra

Ayris, Paul; Lee, Adam F.; Wilson, Kate; Kueppers, Ulrich; Dingwell, Donald B.; Delmelle, Pierre

doi:10.1016/j.gca.2013.02.018

Cited by 72 publications

(116 citation statements)

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“…In-conduit and high-T inplume zones (zones 0 and 1 in Fig. 1) have been investigated previously (Hoshyaripour et al, 2014;Ayris et al, 2013Ayris et al, , 2014. In this study we explore mid-and low-T inplume and warm in-cloud zones (zones 2, 3 and 4 in Fig.…”

Section: Introductionmentioning

confidence: 97%

“…Solubility of iron in airborne particles (e.g., mineral dust) is known to be strongly linked to its chemical speciation and mineralogy (Schroth et al, 2009;Journet et al, 2008). However, it is not yet fully un- Ayris et al (2013), Hort and Gardner (2000) and Rose and Durant (2009) for conduit, plume and cloud zones, respectively; b high-T: T > 600 • C, mid-T: 150 • C < T < 600 • C and low-T: 50 • C < T < 150 • C; c warm zone: T > freezing point (∼ 0 • C), cold zone: T < freezing point.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Large explosive eruptions with deep magma fragmentation are likely to be affected by significant in-conduit gas-tephra interaction at temperatures above 600 • C (Ayris et al, 2013). Such interactions can account for SO 2 scavenging by glass-rich tephra that proceeds by a Ca 2+ diffusion-driven mechanism (Ayris et al, 2013). It is also suggested that high-temperature HCl adsorption prior to the mixing of the erupted material with the ambient air could produce minor quantities of Febearing salts on the ash surface (Ayris et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

“…The formation of liquid coating at the ash surface and its interactions with the surrounding gases (scavenging) and with the ash constituents (dissolution) mainly control the ash iron mobilization. Only the processes within the red dotted line are considered in this study (* Ayris et al, 2013;** Hoshyaripour et al, 2014). of soluble iron-sulfate/chloride/fluoride salts on the ash surface. However, direct theoretical and experimental evidence supporting these hypotheses is required.…”

Section: Introductionmentioning

confidence: 99%

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Ash iron mobilization through physicochemical processing in volcanic eruption plumes: a numerical modeling approach

2015

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Abstract. It has been shown that volcanic ash fertilizes the Fe-limited areas of the surface ocean through releasing soluble iron. As ash iron is mostly insoluble upon the eruption, it is hypothesized that heterogeneous in-plume and in-cloud processing of the ash promote the iron solubilization. Direct evidences concerning such processes are, however, lacking. In this study, a 1-D numerical model is developed to simulate the physicochemical interactions of the gas-ash-aerosol in volcanic eruption plumes focusing on the iron mobilization processes at temperatures between 600 and 0 • C. Results show that sulfuric acid and water vapor condense at ∼ 150 and ∼ 50 • C on the ash surface, respectively. This liquid phase then efficiently scavenges the surrounding gases (> 95 % of HCl, 3-20 % of SO 2 and 12-62 % of HF) forming an extremely acidic coating at the ash surface. The low pH conditions of the aqueous film promote acid-mediated dissolution of the Fe-bearing phases present in the ash material. We estimate that 0.1-33 % of the total iron available at the ash surface is dissolved in the aqueous phase before the freezing point is reached. The efficiency of dissolution is controlled by the halogen content of the erupted gas as well as the mineralogy of the iron at ash surface: elevated halogen concentrations and presence of Fe 2+ -carrying phases lead to the highest dissolution efficiency. Findings of this study are in agreement with the data obtained through leaching experiments.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ash iron mobilization through physicochemical processing in volcanic eruption plumes: a numerical modeling approach

2015

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Nonisothermal viscous sintering of volcanic ash

et al. 2014

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Volcanic ash is often deposited in a hot state. Volcanic ash containing glass, deposited above the glass transition interval, has the potential to sinter viscously both to itself (particle‐particle) and to exposed surfaces. Here we constrain the kinetics of this process experimentally under nonisothermal conditions using standard glasses. In the absence of external load, this process is dominantly driven by surface relaxation. In such cases the sintering process is rate limited by the melt viscosity, the size of the particles and the melt‐vapor interfacial tension. We propose a polydisperse continuum model that describes the transition from a packing of particles to a dense pore‐free melt and evaluate its efficacy in describing the kinetics of volcanic viscous sintering. We apply our model to viscous sintering scenarios for cooling crystal‐poor rhyolitic ash using the 2008 eruption of Chaitén volcano as a case example. We predict that moderate linear cooling rates of > 0.1°C min−1 can result in the common observation of incomplete sintering and the preservation of pore networks.

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Volcanic sulfate aerosol formation in the troposphere

2014

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O) could be an indicator of fractionation (distillation/condensation) processes occurring in volcanic plumes. Here we present analyses of O-and S isotopic compositions of volcanic sulfate absorbed on very fresh volcanic ash from nine moderate historical eruptions in the Northern Hemisphere. Most of our volcanic sulfate samples, which are thought to have been generated in the troposphere or in the tropopause region, do not exhibit any significant mass-independent fractionation (MIF) isotopic anomalies, apart from those from an eruption of a Mexican volcano. Coupled to simple chemistry model calculations representative of the background atmosphere, our data set suggests that although H 2 O 2 (a MIF-carrying oxidant) is thought to be by far the most efficient sulfur oxidant in the background atmosphere, it is probably quickly consumed in large dense tropospheric volcanic plumes. We estimate that in the troposphere, at least, more than 90% of volcanic secondary sulfate is not generated by MIF processes. Volcanic S-bearing gases, mostly SO 2 , appear to be oxidized through channels that do not generate significant isotopically mass-independent sulfate, possibly via OH in the gas phase and/or transition metal ion catalysis in the aqueous phase. It is also likely that some of the sulfates sampled were not entirely produced by atmospheric oxidation processes but came out directly from volcanoes without any MIF anomalies.

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SO2 sequestration in large volcanic eruptions: High-temperature scavenging by tephra

Cited by 72 publications

References 49 publications

Ash iron mobilization through physicochemical processing in volcanic eruption plumes: a numerical modeling approach

Ash iron mobilization through physicochemical processing in volcanic eruption plumes: a numerical modeling approach

Nonisothermal viscous sintering of volcanic ash

Volcanic sulfate aerosol formation in the troposphere

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