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What controls volcano explosivity? Evidence suggests that the syneruptive ascent rate of magma may play an important role; however, this parameter is currently difficult to estimate. We are developing new magma ascent "clocks" to time the journey of magma from source to surface. One such diffusion clock uses water concentration gradients in olivine phenocrysts to constrain the decompression rate of magma during the last few minutes of syneruptive ascent.
Another magma ascent project has involved using olivine-hosted melt inclusions as a volcano thermometer. Crystallization of a rim of olivine on the walls of melt inclusions during the last few minutes to hours of magma ascent and eruption produces an olivine-depleted boundary layer within the melt inclusions. Concentration gradients of MgO in the melt can be used to constrain the thermal history of magma as it ascends the volcanic conduit.
Publications
Mutch, E. J., Newcombe, M. E., & Rudge, J. F. (2024). 3D Diffusion of Water in Melt Inclusion‐Bearing Olivine Phenocrysts. Geochemistry, Geophysics, Geosystems, 25(3), e2023GC011365 https://doi.org/10.1029/2023GC011365
Newcombe, M. E., Plank, T., Barth, A., Asimow, P. D., Hauri, E. (2020). Water-in-olivine magma ascent chronometry: Every crystal is a clock. JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH, 398. 10.1016/j.jvolgeores.2020.106872
Newcombe, M. E., Plank, T., Zhang, Y., Holycross, M., Barth, A., Lloyd, A. S., Ferguson, D., Houghton, B. F., Hauri, E. (2020). Magma Pressure-Temperature-Time Paths During Mafic Explosive Eruptions. FRONTIERS IN EARTH SCIENCE, 8. 10.3389/feart.2020.531911
Barth, A., Newcombe, M., Plank, T., Gonnermann, H., Hajimirza, S., Soto, G. J., Saballos, A., Hauri, E. (2019). Magma decompression rate correlates with explosivity at basaltic volcanoes — Constraints from water diffusion in olivine. Journal of Volcanology and Geothermal Research, 387, 106664. http://dx.doi.org/10.1016/j.jvolgeores.2019.106664 10.1016/j.jvolgeores.2019.106664
Ferriss, E., Plank, T., Newcombe, M., Walker, D., Hauri, E. (2018). Rates of dehydration of olivines from San Carlos and Kilauea Iki. Geochimica et Cosmochimica Acta, 242, 165-190. http://dx.doi.org/10.1016/j.gca.2018.08.050 10.1016/j.gca.2018.08.050
Newcombe, M. E., Fabbrizio, A., Zhang, Y., Ma, C., Le Voyer, M., Guan, Y., Eiler, J. M., Saal, A. E., Stolper, E. M. (2014). Chemical zonation in olivine-hosted melt inclusions. Contributions to Mineralogy and Petrology, 168(1). http://dx.doi.org/10.1007/s00410-014-1030-6 10.1007/s00410-014-1030-6
Image: Eruption of Stromboli; Jens Bludau
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