Experimental Rock Mechanics & Petrology Projects
Strain localization and grain growth in the mantle
On-going plate tectonics relies on maintaining strain localization in the lithospheric mantle below plate boundary faults. Experimental deformation of olivine has helped to map out olivine flow laws at relevant pressures and temperatures, but predictions from some flow laws do not address how strain localization is maintained in highly deformed olivine. We are conducting deformation experiments on olivine aggregates that are characteristic of a fully-recrystallized texture to study deformation mechanisms in highly deformed olivine, the effect of grain growth, and mechanisms for strain localization. We are using a Griggs Rig at Brown University and studying the effect of the deformation using a combination of petrographic techniques, EBSD, and deformation mechanics analyses.
Team Members & Collaborators: Pamela Speciale, Whitney Behr, Greg Hirth
Paleomagnetic properties across the western Gotthard massif
The newly built “Bedretto Underground Laboratory for Geoenergies” is a 5.2 km long tunnel that provides an unparalleled, strike-perpendicular transect through sequences of gneiss and granite. We are investigating the gradient in magnetic properties across the strike of the regional metamorphic fabric. We will connect paleomagnetism, structural geology and petrology to decipher the extent of tectonic overprint in paleomagnetic measurements.
Team Members & Collaborators: Claudio Madonna, Jonas Ruh, Markus Rast
Ti-in-quartz equilibration in the presence of melt
The Ti-in-quartz (TitaniQ) thermobarometer has been used to characterize P-T paths across a range of metamorphic conditions and deformation. The impact of melt in the system on Ti concentrations in quartz – and therefore, the effect on the calculated pressure and/or temperature, has not previously been quantitatively constrained. We plan to conduct TitaniQ experiments that investigate how melt affects the calibration.
Team Members & Collaborators: Ken Christle, Whitney Behr, Olivier Bachmann