Reaction path models of magmatic gas scrubbing

Alessandro Aiuppa, Mariano Valenza, Rossella Di Napoli, Melissa Anne Pfeffer, Evgenia Ilyinskaya, Sylvía Rakel Guðjónsdóttir, Baldur Bergsson, Alessandro Aiuppa, Baldur Bergsson

Risultato della ricerca: Article

2 Citazioni (Scopus)

Abstract

Gas–water–rock reactions taking place within volcano-hosted hydrothermal systems scrub reactive, water-soluble species (sulfur, halogens) from themagmatic gas phase, and as such play amajor control on the composition of surface gasmanifestations. A number of quantitativemodels ofmagmatic gas scrubbing have been proposed in the past,but no systematic comparison ofmodel resultswith observations fromnatural systems has been carried out, to date.Here, we present the results of novel numerical simulations, in which we initialized models of hydrothermal gas–water–rock at conditions relevant to Icelandic volcanism. We focus on Iceland as an example of a “wet” volcanic region where scrubbing iswidespread.Our simulationswere performed (using the EQ3/6 software package) at shallow (temperature < 106 °C; low-Tmodel runs) and deep hydrothermal reservoir (200–250 °C; high-T model runs) conditions. During the simulations, a high-temperaturemagmatic gas phase was added stepwise to an initial meteoricwater, in the presence of a dissolving aquifer rock. At each step, the chemical compositions of coexisting aqueous solution and gas phase were returned by the model. The model-derived aqueous solutions have compositions that describe the maturation path of hydrothermal fluids, from immature, acidic Mg-rich waters, toward Na–Cl-rich mature hydrothermal brines. The modeled compositions are in fair agreement withmeasured compositions of naturalthermal waters and reservoir fluids from Iceland. We additionally show that the composition of the modelgenerated gases is strongly temperature-dependent, and ranges from CO2(g)-dominated (for temperatures ≤80 °C) to H2O(g)-dominated (and more H2S(g) rich) for temperatures >100 °C.We find that this range ofmodel gas compositions reproduces well the (H2O-CO2-STOT) compositional range of reservoir waters and surface gas emissions inIceland. From this validation of the model in an extreme end-member environment of high scrubbing,we conclude that EQ3/6-based reaction path simulations offer a realistic representation of gas–water–rock interaction processes occurring underneath active magmatic-hydrothermal systems.
Lingua originaleEnglish
pagine (da-a)251-269
Numero di pagine19
RivistaChemical Geology
Volume420
Stato di pubblicazionePublished - 2016

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Gases
hydrothermal system
gas
Halogens
Volcanoes
Chemical analysis
Gas emissions
Sulfur
Software packages
halogen
scrub
simulation
volcanism
volcano
Water
sulfur
Computer simulation
software
Temperature
temperature

All Science Journal Classification (ASJC) codes

  • Geology
  • Geochemistry and Petrology

Cita questo

Aiuppa, A., Valenza, M., Di Napoli, R., Pfeffer, M. A., Ilyinskaya, E., Guðjónsdóttir, S. R., ... Bergsson, B. (2016). Reaction path models of magmatic gas scrubbing. Chemical Geology, 420, 251-269.

Reaction path models of magmatic gas scrubbing. / Aiuppa, Alessandro; Valenza, Mariano; Di Napoli, Rossella; Pfeffer, Melissa Anne; Ilyinskaya, Evgenia; Guðjónsdóttir, Sylvía Rakel; Bergsson, Baldur; Aiuppa, Alessandro; Bergsson, Baldur.

In: Chemical Geology, Vol. 420, 2016, pag. 251-269.

Risultato della ricerca: Article

Aiuppa, A, Valenza, M, Di Napoli, R, Pfeffer, MA, Ilyinskaya, E, Guðjónsdóttir, SR, Bergsson, B, Aiuppa, A & Bergsson, B 2016, 'Reaction path models of magmatic gas scrubbing', Chemical Geology, vol. 420, pagg. 251-269.
Aiuppa A, Valenza M, Di Napoli R, Pfeffer MA, Ilyinskaya E, Guðjónsdóttir SR e altri. Reaction path models of magmatic gas scrubbing. Chemical Geology. 2016;420:251-269.
Aiuppa, Alessandro ; Valenza, Mariano ; Di Napoli, Rossella ; Pfeffer, Melissa Anne ; Ilyinskaya, Evgenia ; Guðjónsdóttir, Sylvía Rakel ; Bergsson, Baldur ; Aiuppa, Alessandro ; Bergsson, Baldur. / Reaction path models of magmatic gas scrubbing. In: Chemical Geology. 2016 ; Vol. 420. pagg. 251-269.
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title = "Reaction path models of magmatic gas scrubbing",
abstract = "Gas–water–rock reactions taking place within volcano-hosted hydrothermal systems scrub reactive, water-soluble species (sulfur, halogens) from themagmatic gas phase, and as such play amajor control on the composition of surface gasmanifestations. A number of quantitativemodels ofmagmatic gas scrubbing have been proposed in the past,but no systematic comparison ofmodel resultswith observations fromnatural systems has been carried out, to date.Here, we present the results of novel numerical simulations, in which we initialized models of hydrothermal gas–water–rock at conditions relevant to Icelandic volcanism. We focus on Iceland as an example of a “wet” volcanic region where scrubbing iswidespread.Our simulationswere performed (using the EQ3/6 software package) at shallow (temperature < 106 °C; low-Tmodel runs) and deep hydrothermal reservoir (200–250 °C; high-T model runs) conditions. During the simulations, a high-temperaturemagmatic gas phase was added stepwise to an initial meteoricwater, in the presence of a dissolving aquifer rock. At each step, the chemical compositions of coexisting aqueous solution and gas phase were returned by the model. The model-derived aqueous solutions have compositions that describe the maturation path of hydrothermal fluids, from immature, acidic Mg-rich waters, toward Na–Cl-rich mature hydrothermal brines. The modeled compositions are in fair agreement withmeasured compositions of naturalthermal waters and reservoir fluids from Iceland. We additionally show that the composition of the modelgenerated gases is strongly temperature-dependent, and ranges from CO2(g)-dominated (for temperatures ≤80 °C) to H2O(g)-dominated (and more H2S(g) rich) for temperatures >100 °C.We find that this range ofmodel gas compositions reproduces well the (H2O-CO2-STOT) compositional range of reservoir waters and surface gas emissions inIceland. From this validation of the model in an extreme end-member environment of high scrubbing,we conclude that EQ3/6-based reaction path simulations offer a realistic representation of gas–water–rock interaction processes occurring underneath active magmatic-hydrothermal systems.",
author = "Alessandro Aiuppa and Mariano Valenza and {Di Napoli}, Rossella and Pfeffer, {Melissa Anne} and Evgenia Ilyinskaya and Gu{\dh}j{\'o}nsd{\'o}ttir, {Sylv{\'i}a Rakel} and Baldur Bergsson and Alessandro Aiuppa and Baldur Bergsson",
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T1 - Reaction path models of magmatic gas scrubbing

AU - Aiuppa, Alessandro

AU - Valenza, Mariano

AU - Di Napoli, Rossella

AU - Pfeffer, Melissa Anne

AU - Ilyinskaya, Evgenia

AU - Guðjónsdóttir, Sylvía Rakel

AU - Bergsson, Baldur

AU - Aiuppa, Alessandro

AU - Bergsson, Baldur

PY - 2016

Y1 - 2016

N2 - Gas–water–rock reactions taking place within volcano-hosted hydrothermal systems scrub reactive, water-soluble species (sulfur, halogens) from themagmatic gas phase, and as such play amajor control on the composition of surface gasmanifestations. A number of quantitativemodels ofmagmatic gas scrubbing have been proposed in the past,but no systematic comparison ofmodel resultswith observations fromnatural systems has been carried out, to date.Here, we present the results of novel numerical simulations, in which we initialized models of hydrothermal gas–water–rock at conditions relevant to Icelandic volcanism. We focus on Iceland as an example of a “wet” volcanic region where scrubbing iswidespread.Our simulationswere performed (using the EQ3/6 software package) at shallow (temperature < 106 °C; low-Tmodel runs) and deep hydrothermal reservoir (200–250 °C; high-T model runs) conditions. During the simulations, a high-temperaturemagmatic gas phase was added stepwise to an initial meteoricwater, in the presence of a dissolving aquifer rock. At each step, the chemical compositions of coexisting aqueous solution and gas phase were returned by the model. The model-derived aqueous solutions have compositions that describe the maturation path of hydrothermal fluids, from immature, acidic Mg-rich waters, toward Na–Cl-rich mature hydrothermal brines. The modeled compositions are in fair agreement withmeasured compositions of naturalthermal waters and reservoir fluids from Iceland. We additionally show that the composition of the modelgenerated gases is strongly temperature-dependent, and ranges from CO2(g)-dominated (for temperatures ≤80 °C) to H2O(g)-dominated (and more H2S(g) rich) for temperatures >100 °C.We find that this range ofmodel gas compositions reproduces well the (H2O-CO2-STOT) compositional range of reservoir waters and surface gas emissions inIceland. From this validation of the model in an extreme end-member environment of high scrubbing,we conclude that EQ3/6-based reaction path simulations offer a realistic representation of gas–water–rock interaction processes occurring underneath active magmatic-hydrothermal systems.

AB - Gas–water–rock reactions taking place within volcano-hosted hydrothermal systems scrub reactive, water-soluble species (sulfur, halogens) from themagmatic gas phase, and as such play amajor control on the composition of surface gasmanifestations. A number of quantitativemodels ofmagmatic gas scrubbing have been proposed in the past,but no systematic comparison ofmodel resultswith observations fromnatural systems has been carried out, to date.Here, we present the results of novel numerical simulations, in which we initialized models of hydrothermal gas–water–rock at conditions relevant to Icelandic volcanism. We focus on Iceland as an example of a “wet” volcanic region where scrubbing iswidespread.Our simulationswere performed (using the EQ3/6 software package) at shallow (temperature < 106 °C; low-Tmodel runs) and deep hydrothermal reservoir (200–250 °C; high-T model runs) conditions. During the simulations, a high-temperaturemagmatic gas phase was added stepwise to an initial meteoricwater, in the presence of a dissolving aquifer rock. At each step, the chemical compositions of coexisting aqueous solution and gas phase were returned by the model. The model-derived aqueous solutions have compositions that describe the maturation path of hydrothermal fluids, from immature, acidic Mg-rich waters, toward Na–Cl-rich mature hydrothermal brines. The modeled compositions are in fair agreement withmeasured compositions of naturalthermal waters and reservoir fluids from Iceland. We additionally show that the composition of the modelgenerated gases is strongly temperature-dependent, and ranges from CO2(g)-dominated (for temperatures ≤80 °C) to H2O(g)-dominated (and more H2S(g) rich) for temperatures >100 °C.We find that this range ofmodel gas compositions reproduces well the (H2O-CO2-STOT) compositional range of reservoir waters and surface gas emissions inIceland. From this validation of the model in an extreme end-member environment of high scrubbing,we conclude that EQ3/6-based reaction path simulations offer a realistic representation of gas–water–rock interaction processes occurring underneath active magmatic-hydrothermal systems.

UR - http://hdl.handle.net/10447/172892

M3 - Article

VL - 420

SP - 251

EP - 269

JO - Chemical Geology

JF - Chemical Geology

SN - 0009-2541

ER -