Trace element emissions during the 2018 Kilauea Lower East Rift Zone eruption
- 1University of Cambridge, Department of Earth Sciences, Cambridge, UK (em572@cam.ac.uk)
- 2University College London, Department of Earth Sciences, UK
- 3University of Leeds, School of Earth and Environment, UK
- 4University of Oxford, Department of Earth Sciences, UK
- 5USGS Hawaiian Volcano Observatory, USA
- 6USGS, Baltimore, MD, USA
- 7USGS Cascades Volcano Observatory, USA
- 8USGS Alaska Volcano Observatory, USA
- 9University of Cambridge, Department of Geography, UK
The 2018 eruption on the Lower East Rift Zone of Kilauea volcano, Hawai’i released unprecedented fluxes of gases (>200 kt/d SO2) and aerosol into the troposphere [1,2]. The eruption affected air quality across the island and lava flows reached the ocean, forming a halogen-rich plume as lava rapidly boiled and evaporated seawater.
We present the at-source composition – gas and size-segregated aerosol – of both the magmatic plume (emitted from ‘Fissure 8’, F8) and the lava-seawater interaction plume (ocean entry, OE), including major gas species, and major and trace elements in non-silicate aerosol. Trace metal and metalloid (TMM) emissions during the 2018 eruption were the highest recorded for Kilauea, and the magmatic ‘fingerprint’ of TMMs (X/SO2 ratios) in the 2018 plume is consistent with measurements made at the summit lava lake in 2008 [3], and with other rift and hotspot volcanoes [4,5].
We show that the OE plume composition predominantly reflects seawater composition with a small contribution from plagioclase +/- ash. However, elevated concentrations of some TMMs (Bi, Cd, Cu, Zn, Ag) with affinity for Cl-speciation in the gas phase cannot be accounted for by the silicate correction and therefore may derive from degassing of lava in the presence of elevated Cl-. In the case of silver and copper, concentrations in the OE plume are elevated above both the F8 plume and seawater.
At-vent speciation of TMMs in the F8 plume during oxidation (following a correction for ash contributions) was assessed using a Gibbs Energy Minimization algorithm (HSC chemistry, Outotec Research). We also demonstrate the sensitivity of speciation in the plume to the concentration of common ligand-forming elements, chlorine and sulfur. These results could be used as initial conditions in atmospheric reaction models to investigate how plume composition evolves as low-temperature chemistry takes over.
References:
[1] Neal C et al. (2019) Science
[2] Kern C et al. (2019) AGU Fall meeting abstract V43C-0209
[3] Mather T et al. (2012) GCA 83:292-323
[4] Zelenzki et al. (2013) Chem Geol 357:95-116
[5] Gauthier P-J et al. (2016) J Geophys 121:1610-1630
How to cite: Mason, E., Wieser, P., Liu, E., Ilyinskaya, E., Edmonds, M., Whitty, R. C. W., Mather, T., Elias, T., Nadeau, P. A., Kern, C., Schneider, D. J., and Oppenheimer, C.: Trace element emissions during the 2018 Kilauea Lower East Rift Zone eruption, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-162, https://doi.org/10.5194/egusphere-egu2020-162, 2019