Crunchy with Crystals: unravelling the eruptive pathways of the domes and flows of the Morne Plat Plays volcanic complex, Dominica

The Plat Plays volcanic complex in southern Dominica hosts a complex of volcanic domes, including Morne Patates the site of Dominica’s most recent volcanism (685 ± 55 years B.P).
Both dense dome and vesiculated air fall samples are remarkably crystalline (49-63%). These crystals represent a cargo crystallised (or swept in) as andesitic to dacitic bulk melts made their way to the surface through a vertically extensive storage zone. But the late-stage history preserved in crystal and rock textures is underexplored.

Recent analysis suggest these samples are on the limits of eruptibility and should struggle to erupt explosively. So just how and why did these magmas erupt?

This PhD would begin with fieldwork, collecting stratigraphically constrained samples to reconstruct the changing state of the magma(s) as they reached the surface. Further work would include a subset of: microtextural analysis, experimental petrology, modelling the ascending magma, mapping and analysis of the relationship between surface structures and geometry of this complex and others on Dominica.

Can we use this information to understand the subsurface rise of potential future eruptions, and their transitions? Ultimately, this end member crystallinity system could allow us to understand similar magmas worldwide.