Name: Catherine Gallagher
Project Title: “The sources, mechanisms and timing of volatile loss accompanying large-volume basaltic volcanism”
Project Partner: British Geological Survey
A volcanic eruption’s ability to release sulphur (S) gases into the atmosphere is one of the critical factors in assessing their climatic and environmental impact, because it is directly linked to the potential H2SO4 atmospheric burden produced. Basaltic fissure eruptions loft large amounts of S into the atmosphere because of the efficient degassing of volatiles and halogens from the magma at the vent, coupled with the high S yield of basaltic magma. The common nature of this style of eruption and its products, regardless of magnitude, means that our understanding of the exact processes which influence atmospheric chemistry and environmental impact is very important.
This study uses established petrological and novel geochemical proxies to assess the sources, mechanisms and timing of volatile loss of basaltic volcanism. Primarily, to calculate the total atmospheric S burden of these events, whilst also constraining which S species was lost and its source. This project is utilising well-documented historical Icelandic eruptions such as Lakagígar 1783-1784 and Nornahraun (Bárðarbunga) 2014-2015. The latter eruption has given us the opportunity to use real-time S gas and aerosol emission data to test the petrological and geochemical methods upon which this project hinges. This aims to obtain better constraint the atmospheric effects of these historical eruptions, with the intention to use these tested methods to improve estimates of the climatic effects of larger-scale basaltic eruptions. In turn shedding light on the postulated association of flood basaltic eruptions with major mass extinction events.
My research interests also include the effects of degassing and effusion rates of basaltic effusive lava-producing eruptions on: lava rheology, consequent thermal efficiency of transport systems and therefore the lava morphology emplaced. This has a specific aim: to piece together the reasons for critical flow length of basaltic lavas, a phenomenon unique to Iceland, for hazard mapping purposes.
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