SO2 scavenging potential of fractured permeable rhyolitic domes
Abstract
Hot volcanic gases released during large volcanic eruptions can be removed from the atmosphere (i.e. gas scavenging), due to high-temperature adsorption and subsequent crystal growth on the surface of glassy ash particles. This has been shown to be a feasible mechanism in hot volcanic plumes and in conduits above the fragmentation front. However, the possibility of scavenging occurring during outgassing through permeable volcanic domes has never been considered, despite the conditions being favorable for gas scavenging. Namely, volcanic domes can reside at high temperatures gas residence times can be high, providing ample opportunity for gas-glass interactions. We have conducted experiments to evaluate the potential for rhyolitic glass to scavenge SO2 at high temperatures and then we have applied our results to an in-dome scenario (to the Chaitén volcano 2008 rhyolitic dome). We evaluated the effect of grain size distribution of glassy ash trapped in dome fractures, dome residence temperature, exposure time and water vapour content, on SO2 scavenging. We hypothesize that, the ash-filled fracture networks through which hot volcanic gases pass, are indeed capable of scavenging considerable amounts of SO2, HCl, and other gases. Our findings provide a mechanism for understanding SO2 anomalies measured in plume gases during rhyolitic dome-forming eruptions. Further work will include integrating our findings to plume dispersion models, allowing better environmental impacts assessment of large volcanic eruptions.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.V12B..05C
- Keywords:
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- 8428 Explosive volcanism;
- VOLCANOLOGY;
- 8434 Magma migration and fragmentation;
- VOLCANOLOGY;
- 8445 Experimental volcanism;
- VOLCANOLOGY;
- 8486 Field relationships;
- VOLCANOLOGY