Name: Catherine Gallagher

Project Title:The sources, mechanisms and timing of volatile loss accompanying large-volume basaltic volcanism

Cohort: 2014/15

Institutions: The University of Durham and the University of Iceland (Joint PhD project).

Project Partner: British Geological Survey


PhD Project:

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.

Conference Talks:

  • The mode of emplacement of the Nornahraun (Bárðarbunga) flow field. Remote sensing workshop: Remote sensing of active volcanic vents and lava flows and its implication for monitoring of the ongoing Nornahraun eruption. The University of Iceland (2014).
  • Flow morphology and the mode of emplacement of the Nornahraun flow field. Jarðfræðafélag Íslands (Geological Society of Iceland, Fall Meeting 2014). Published abstract.
  • Volatile loss during basaltic-lava producing eruptions: investigations into the source of volatile saturation and its redox conditions (IAPETUS conference 2015).
  • The source and impact of geochemical heterogeneities in lava flows on the potential atmospheric sulphur burden of flood basalt eruptions. IAVCEI (IUGG) 2015 conference Published abstract.

Posters with accompanying published abstracts:

  • Quantifying the atmospheric sulphur burden of basaltic fissure eruptions. VERTIGO summer school (Spring 2015). Published poster.
  • Nord-Min 2015 conference (Spring 2015): Investigations into the mechanisms driving sulphur saturation and oversaturation within the earliest emplaced basaltic lavas from fissure eruptions.
  • Quantifying the atmospheric burden of basaltic lava-producing fissure eruptions. A case study Nornahraun, North Iceland, 2014-2015. EGU 2015 conference. Published abstract.
  • Investigations into the source of volatile saturation for various basaltic-lava producing eruptions: and the influence of the redox source conditions on the S species lost (Goldschmidt 2015).

Get in touch:

Email:  and


  • Durham Office: Department of Earth Sciences, open plan area, desk 71.
  • Icelandic office: Institute of Earth Sciences, Háskóli Íslands (The University of Iceland), Office 263, Office Telephone: (+354) 5254374.