Dr. Mathieu Colombier
Postdoc
I have started to study volcanology during my Master at the Laboratoire Magmas et Volcans of Clermond-Ferrand in France, and then moved to LMU in Munich in 2015 to do my PhD on the role of the percolation threshold and water-magma interaction on volcanic eruptive style, supervised by Donald Dingwell, Bettina Scheu and Ulrich Kueppers. After completing my PhD in 2018 I got a 4-year position as assistant professor at LMU. Since 2022, I am a post-doctoral researcher at LMU.
Research Interests
My research aims to quantify eruptive processes spanning from magma degassing and fragmentation in volcanic conduits to the impact of volcanic ash clouds on the atmosphere. I combine vesiculation experiments and 3D and 4D textural analysis of natural and experimental products to shed light on the link between bubble formation, shearing, crystallization and outgassing vs. fragmentation during effusive-explosive transitions. In addition, part of my research focuses on magma-seawater interaction during submarine eruptions and impacts for populations and climate.
Pore connectivity and permeability in magma and volcanic rocks
In this topic I aim to shed light on the impact of the percolation threshold and subsequent development of pore connectivity and permeability on the efficiency of outgassing vs. pore pressurization. This transition from closed- to open-system degassing may occur via a combination of processes in the conduit, such as vesiculation, pore collapse, brittle fracturing, fragmentation and subsequent ash sintering. I combine here 2D and 3D textural analysis and petro-physical measurements of natural volcanic rocks, 4D vesiculation experiments at the synchrotron and percolation models in order to quantify the percolation threshold and connectivity evolution in a range of volcanic conditions. The ultimate goal is to quantify the impact of polydispersivity, shear, crystal content and viscosity on percolation and consequences for volcanic eruptive style.
Colombier, M., Wadsworth, F. B., Gurioli, L., Scheu, B., Kueppers, U., Di Muro, A., & Dingwell, D. B. (2017). The evolution of pore connectivity in volcanic rocks. Earth and planetary science letters, 462, 99-109.
Colombier, M., Wadsworth, F. B., Scheu, B., Vasseur, J., Dobson, K. J., Cáceres, F., ... & Dingwell, D. B. (2020). In situ observation of the percolation threshold in multiphase magma analogues. Bulletin of volcanology, 82(4), 32.
Colombier, M., Vasseur, J., Houghton, B. F., Cáceres, F., Scheu, B., Kueppers, U., ... & Dingwell, D. B. (2021). Degassing and gas percolation in basaltic magmas. Earth and Planetary Science Letters, 573, 117134.
Submarine volcanism
This topic envelopes several aspects of magma-seawater interaction during explosive submarine volcanic eruptions, such as magma fragmentation, ash generation and subsequent aggregation, the link between quenching and vesiculation to create transitional textures, salt formation by gas scavenging vs. seawater precipitation and impact of these processes on the atmosphere. I use a multidisciplinary approach including textural characterization, chemical analysis (glass chemistry, leaching, evolved gas analysis, isotopic measurements) of submarine volcanic products, thermal modelling, ash properties and satellite remote sensing in order to constrain the effect of magma-seawater interaction on eruptive processes, gas vs. ash budgets and consequences for volcanic ash transport, atmosphere chemistry and climate.
Colombier, M., Scheu, B., Wadsworth, F. B., Cronin, S., Vasseur, J., Dobson, K. J., ... & Dingwell, D. B. (2018). Vesiculation and quenching during surtseyan eruptions at Hunga Tonga‐Hunga Ha'apai Volcano, Tonga. Journal of Geophysical Research: Solid Earth, 123(5), 3762-3779.
Colombier, M., Mueller, S. B., Kueppers, U., Scheu, B., Delmelle, P., Cimarelli, C., ... & Dingwell, D. B. (2019). Diversity of soluble salt concentrations on volcanic ash aggregates from a variety of eruption types and deposits. Bulletin of Volcanology, 81(7), 39.
Colombier, M., Ukstins, I. A., Tegtmeier, S., Scheu, B., Cronin, S. J., Thivet, S., ... & Dingwell, D. B. (2023). Atmosphere injection of sea salts during large explosive submarine volcanic eruptions. Scientific Reports, 13(1), 14435.
Advances in X-ray micro- and nano-tomography applied to volcanic rocks
This topic relates to the new possibilities offered by 3D and 4D imaging of volcanic rocks using micro- and nano-tomography. I am currently using these techniques to study melt inclusions and associated fluid inclusions at the nano-scale and in 3D, refining previous estimates of bubble/melt ratio using classical 2D approach. I am also investigating the relationship between the fragmentation mechanism, crack propagation, bubble size distribution and resulting morphology of single volcanic ash particles. Finally, I am also investigating in situ vesiculation in obsidians, allowing to look at the localised and transient nature of bubble growth and permeability development, and the impact of shear and crystal content on these processes.
Colombier, M., Scheu, B., Kueppers, U., Cronin, S. J., Mueller, S. B., Hess, K. U., ... & Dingwell, D. B. (2019). In situ granulation by thermal stress during subaqueous volcanic eruptions. Geology, 47(2), 179-182.
Colombier, M., Manga, M., Wright, H., Bernard, B., deGraffenried, R., Caceres, F., ... & Dingwell, D. B. (2023). Pre‐Eruptive Outgassing and Pressurization, and Post‐Fragmentation Bubble Nucleation, Recorded by Vesicles in Breadcrust Bombs From Vulcanian Activity at Guagua Pichincha Volcano, Ecuador. Journal of Geophysical Research: Solid Earth, 128(9), e2023JB026775.