Mattia Pistone

EMRP Earth Magnetism & Rock Physics

The 2012 Outstanding Student Poster (OSP) Award is awarded to Mattia Pistone for the poster/PICO entitled:

Rheology of Three-Phase Magmas (Pistone, M.; Caricchi, L.; Ulmer, P.; Reusser, E.; Marone, F.; Burlini, L.)

Click here to download the poster/PICO file.

Mattia Pistone is a PhD student at the Institute for Geochemistry and Petrology at ETH Zurich (Switzerland). In my PhD project (SNF; grant 200020-120221) I have experimentally investigated the rheology of three-phase magmas (composed of crystals, gas bubbles and silicate melt in different relative proportions) under simple shear deformation at high temperature and high pressure conditions at Rock Deformation Laboratory at ETH Zurich. In my poster I present new experimental results showing two Non-Newtonian behaviors: shear thinning (decrease of viscosity with increasing strain rate) at high crystallinity; shear thickening (increase of viscosity with increasing strain rate) at low crystallinity. Shear thinning is associated with crystal size reduction and shear banding. Shear thickening is the expression of bubble coalescence and outgassing. The microstructural and rheological results have been combined to constrain the flow mechanics of three-phase magmas. This work is also published in Journal of Geophysical Research (doi:10.1029/2011JB008986).