Basaltic volcanoes can display a wide range of eruptive styles and intensities, from lava effusion and lava fountains to more explosive activity. This diversity reflects the evolution of magma from storage at depth, through ascent, to eruption at the surface. Volcanic products, including bombs, lapilli, ash, and, where relevant, lava samples, preserve valuable information on the processes controlling magma degassing, crystallization, vesiculation, fragmentation, and cooling.
This Master’s project will investigate stratigraphically well-constrained eruptive products to reconstruct the physical and chemical evolution of magma and its relationship with changes in eruptive style and intensity. The main objectives are to determine: (1 – pre-eruptive) how magma storage, crystallization, and degassing processes controlled the physical properties of the magma prior to eruption; (2 – syn-eruptive) how vesiculation, magma rheology, ascent, and fragmentation evolved during the eruptive sequence; and (3 – eruption-scale) how these processes can be related to transitions between effusive and explosive activity, as well as to changes in the intensity and duration of the eruption.
The analytical work will combine pre-existing field observations with complementary petrological and geochemical techniques. Macro- to microscale characterization of the samples may include grain-size analysis, clast morphology and componentry, density and porosity measurements, vesicle- and crystal-size distributions, optical and scanning electron microscopy, quantitative image analysis, and X-ray computed tomography. Bulk-rock, glass, and mineral compositions may also be used to constrain the geochemical evolution of the studied magmatic systems and complement the petrological dataset.
The case study and analytical programme will be defined according to the student’s interests. Samples and datasets are available from Etna (Sicily, Italy), Kīlauea (Hawai‘i, USA), and Tenerife (Canary Islands, Spain), allowing the investigation of historical or recent eruptions with contrasting dynamics. This flexible framework will enable the development of a focused project while contributing to a broader understanding of the processes controlling volcanic hazards at basaltic volcanoes.
Advisors: Dr. Simon Thivet
University: FR