Modern and past volcanic degassing of iodine

Bureau, Hélène; Auzende, Anne-Line; Marocchi, Marta; Raepsaet, Caroline; Munsch, P.; Testemale, Denis; Mézouar, M.; Kubsky, S.; Carrière, Marie; Ricolleau, A.; Fiquet, G.

doi:10.1016/j.gca.2015.10.017

Cited by 36 publications

(30 citation statements)

References 70 publications

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“…Because the pressure dependency of the volatile solubility is different for each particular volatile species, molar ratios of major gas constituents in volcanic plumes are discussed as accessible F. Dinger et al: BrO/SO 2 molar ratios in the volcanic gas plume of Cotopaxi and suitable proxies for the magma pressure and degassing depth. In particular carbon-to-sulfur (Burton et al, 2007) and halogen-to-sulfur ratios, such as chlorine-to-sulfur (Edmonds et al, 2001) and bromine-to-sulfur (Bobrowski and Giuffrida, 2012) ratios, turned out to be powerful tools sensitive to events of magma influx at depth and the arrival of magma in shallow zones of the magmatic system.…”

Section: Introductionmentioning

confidence: 99%

Periodicity in the BrO∕SO<sub>2</sub> molar ratios in the volcanic gas plume of Cotopaxi and its correlation with the Earth tides during the eruption in 2015

et al. 2018

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Abstract. We evaluated NOVAC (Network for Observation of Volcanic and Atmospheric Change) gas emission data from the 2015 eruption of the Cotopaxi volcano (Ecuador) for BrO∕SO2 molar ratios. The BrO∕SO2 molar ratios were very small prior to the phreatomagmatic explosions in August 2015, significantly higher after the explosions, and continuously increasing until the end of the unrest period in December 2015. These observations together with similar findings in previous studies at other volcanoes (Mt. Etna, Nevado del Ruiz, Tungurahua) suggest a possible link between a drop in BrO∕SO2 and a future explosion. In addition, the observed relatively high BrO∕SO2 molar ratios after December 2015 imply that bromine degassed predominately after sulfur from the magmatic melt. Furthermore, statistical analysis of the data revealed a conspicuous periodic pattern with a periodicity of about 2 weeks in a 3-month time series. While the time series is too short to rule out a chance recurrence of transient geological or meteorological events as a possible origin for the periodic signal, we nevertheless took this observation as a motivation to examine the influence of natural forcings with periodicities of around 2 weeks on volcanic gas emissions. One strong aspirant with such a periodicity are the Earth tides, which are thus central in this study. We present the BrO∕SO2 data, analyse the reliability of the periodic signal, discuss a possible meteorological or eruption-induced origin of this signal, and compare the signal with the theoretical ground surface displacement pattern caused by the Earth tides. Our central result is the observation of a significant correlation between the BrO∕SO2 molar ratios with the north–south and vertical components of the calculated tide-induced surface displacement with correlation coefficients of 47 and 36 %, respectively. From all other investigated parameters, only the correlation between the BrO∕SO2 molar ratios and the relative humidity in the local atmosphere resulted in a comparable correlation coefficient of about 33 %.

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Section: Introductionmentioning

confidence: 99%

Periodicity in the BrO∕SO<sub>2</sub> molar ratios in the volcanic gas plume of Cotopaxi and its correlation with the Earth tides during the eruption in 2015

et al. 2018

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“…This incompatible nature, coupled with their volatile behaviour, implies that halogen elements will preferentially enter silicate melts and aqueous fluids during geological processes such as melting, degassing, and dehydration reactions. Bureau et al (2010), Dalou et al (2012) and Bureau et al (2016) have shown experimentally that halogens show strong partitioning into silicate melts and fluid phases at conditions typical of the upper mantle. The incompatible nature of halogen elements suggests that they should not be fractionated from one another during these processes, and therefore, they make for ideal tracers of volatile transport between major geological reservoirs (Schilling et al 1980;Ito et al 1983;Jambon et al 1995).…”

Section: Introductionmentioning

confidence: 99%

Fluorine partitioning between humite-group minerals and aqueous fluids: implications for volatile storage in the upper mantle

Hughes

Pawley

2019

Contrib Mineral Petrol

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Phase equilibrium experiments were performed in the MgO-SiO 2-H 2 O system, along with fluorine (MSH + F), at conditions between 800-1000 °C and 2.0-2.5 GPa to constrain the solubility of fluorine in humite-group minerals and to determine fluorine partitioning between humite-group minerals and aqueous fluid. Fluorine solubility in humite-group minerals ranges between ~ 1 and 11 wt% F and is dependent on the salinity of the fluid (~ 0.2-3.5 wt% F), indicating that humitegroup minerals have exceedingly high saturation limits for F and that a full solid solution between F − and OH − is possible within the crystal structure. Raman spectroscopy reveals the preferential ordering of F, promoting the formation of a stable OH-F bond. Mineral-fluid partition coefficients are always greater than unity, with average coefficients of D F clinohumite/fluid = 3, D F humite/fluid = 2, D F chondrodite/fluid = 4, and D F norbergite/fluid = 4. Partition coefficients are independent of pressure or temperature, but decrease with increasing fluid salinity. Fluorine is, therefore, highly soluble and compatible within this group of ultramafic mantle minerals. High solubility and mineral-fluid partition coefficients, together with wide stability fields in pressure and temperature space, demonstrate that humite-group minerals are potential storage sites for F, and by extension H 2 O, during subduction. Upon the breakdown of less stable hydrous and/or fluorine-rich phases during lower grades of subduction zone metamorphism, fluorine may redistribute into phases such as humite-group minerals and be transported beyond the volcanic arc and to the upper mantle.

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“…It should be noted that the above estimate does not take into account the degassing of iodine from mantle melts in the course of crust formation [Bureau et al, 2016]: the iodine condensation temperature, ≈ 400 ∘ C, is significantly lower than the temperature of silicate melts ≈ 1400 ∘ C. This again confirms the correct choice of a low concentration of 127 I BSE , and, accordingly, the low value of 129 Xe(I)/ 136 Xe(Pu) CRUST .…”

Section: Nucleogenic Xenon Isotopes In the Mantlementioning

confidence: 67%

The late Earth's accretion: Processes and materials

Tolstikhin¹

2018

Russ. J. Earth Sci.

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In accord with the standard Earth accretion scenario, the late accretion supervened the last collision with a massive proto-planet, segregation of the core, and (partial) solidification of the magma ocean. These processes took place ≈ 40 Ma after Sun formation or somewhat later. Traces of the processes and respective materials have been preserved as specific elemental and isotopic abundances in the earth's mantle. Pu-238 U-129 I-Xe systematics trace the accreting materials and the rate of mantle mixing and degassing. Recently proposed interpretations of this last systematics appear to be precarious and are particularly discussed in this contribution. During the late accretion a terrestrial regolith, including chondritic and solar-wind-irradiated materials, was rapidly accumulating on the surface of the early thick basaltic crust, enriched in incompatible elements. This early crust had not been preserved. Its overturn(s) into the mantle during several 100th Ma after Sun formation and (partial) isolation from the mantle convection allow all principal observations, related to the informative systematics mentioned above, to be satisfied, providing the transfer of the crust®olith "cake" was not accompanying by fractionation and degassing, in contrast to present-day slab subduction.

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Modern and past volcanic degassing of iodine

Cited by 36 publications

References 70 publications

Periodicity in the BrO∕SO<sub>2</sub> molar ratios in the volcanic gas plume of Cotopaxi and its correlation with the Earth tides during the eruption in 2015

Periodicity in the BrO∕SO<sub>2</sub> molar ratios in the volcanic gas plume of Cotopaxi and its correlation with the Earth tides during the eruption in 2015

Fluorine partitioning between humite-group minerals and aqueous fluids: implications for volatile storage in the upper mantle

The late Earth's accretion: Processes and materials

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Modern and past volcanic degassing of iodine

Cited by 36 publications

References 70 publications

Periodicity in the BrO∕SO&lt;sub&gt;2&lt;/sub&gt; molar ratios in the volcanic gas plume of Cotopaxi and its correlation with the Earth tides during the eruption in 2015

Periodicity in the BrO∕SO&lt;sub&gt;2&lt;/sub&gt; molar ratios in the volcanic gas plume of Cotopaxi and its correlation with the Earth tides during the eruption in 2015

Fluorine partitioning between humite-group minerals and aqueous fluids: implications for volatile storage in the upper mantle

The late Earth's accretion: Processes and materials

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Periodicity in the BrO∕SO<sub>2</sub> molar ratios in the volcanic gas plume of Cotopaxi and its correlation with the Earth tides during the eruption in 2015

Periodicity in the BrO∕SO<sub>2</sub> molar ratios in the volcanic gas plume of Cotopaxi and its correlation with the Earth tides during the eruption in 2015