We used a Multi-component Gas Analyser System (Multi-GAS) to measure, for the very first time, the composition (H2O, CO2, H2S, SO2) of the volcanic gas plume issuing from the Boiling Lake, a vigorously degassing, hot (T ~ 80-90°C) volcanic lake in Dominica, West Indies. The Multi- GAS captured in-plume concentrations of H2O, CO2 and H2S were well above those typical of ambient atmosphere, while no volcanic SO2 was detected (<0.05 ppm). These were used to derive the Boiling Lake plume characteristic ratios of CO2/H2S (5.2±0.4) and H2O/CO2 (31.4±6). Assuming that other volcanic gas species (e.g., HCl, CO, H2, N2, etc.) are absent in the plume, we recalculated a (air-free) composition for the sourcing volcanic gases of ~ 96.3% H2O, 3.1% CO2 and 0.6% H2S. This hydrous gas composition is within the range of published gas compositions in the Lesser Antilles region, and slightly more H2O-rich than obtained for the fumaroles of the nearby Valley of Desolation (~94.4% H2O, 4.7% CO2 and 0.8% H2S; CO2/H2S of ~5.7). We use our results, in tandem with the output of numerical simulations of gas scrubbing in the lake-water (performed via the EQ3/6 software), to derive new constraints on the degassing mechanisms at this poorly studied (but potentially hazardous) volcanic lake.

Di Napoli, R., Aiuppa, A., & Allard P (2013). A first Multi-GAS based characterisation of the Boiling Lake's (Dominica, Lesser Antilles) volcanic gas plume. ANNALS OF GEOPHYSICS, 56 [10.4401/ag-6277].

A first Multi-GAS based characterisation of the Boiling Lake's (Dominica, Lesser Antilles) volcanic gas plume

DI NAPOLI, Rossella;AIUPPA, Alessandro;
2013

Abstract

We used a Multi-component Gas Analyser System (Multi-GAS) to measure, for the very first time, the composition (H2O, CO2, H2S, SO2) of the volcanic gas plume issuing from the Boiling Lake, a vigorously degassing, hot (T ~ 80-90°C) volcanic lake in Dominica, West Indies. The Multi- GAS captured in-plume concentrations of H2O, CO2 and H2S were well above those typical of ambient atmosphere, while no volcanic SO2 was detected (<0.05 ppm). These were used to derive the Boiling Lake plume characteristic ratios of CO2/H2S (5.2±0.4) and H2O/CO2 (31.4±6). Assuming that other volcanic gas species (e.g., HCl, CO, H2, N2, etc.) are absent in the plume, we recalculated a (air-free) composition for the sourcing volcanic gases of ~ 96.3% H2O, 3.1% CO2 and 0.6% H2S. This hydrous gas composition is within the range of published gas compositions in the Lesser Antilles region, and slightly more H2O-rich than obtained for the fumaroles of the nearby Valley of Desolation (~94.4% H2O, 4.7% CO2 and 0.8% H2S; CO2/H2S of ~5.7). We use our results, in tandem with the output of numerical simulations of gas scrubbing in the lake-water (performed via the EQ3/6 software), to derive new constraints on the degassing mechanisms at this poorly studied (but potentially hazardous) volcanic lake.
Settore GEO/08 - Geochimica E Vulcanologia
Di Napoli, R., Aiuppa, A., & Allard P (2013). A first Multi-GAS based characterisation of the Boiling Lake's (Dominica, Lesser Antilles) volcanic gas plume. ANNALS OF GEOPHYSICS, 56 [10.4401/ag-6277].
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10447/87765
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