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I collect and study xenoliths, rocks that come up from lower crust and upper mantle depths through volcanic eruptions.

My research aims to understand the rheological properties of the lower crust and upper mantle, primarily in the Mojave region of Southeastern California. I'm also actively working on understanding the factors that influence the development of olivine lattice preferred orientation (LPO) more generally. Recently, I've been working towards exploring the effects water and stress have on olivine LPO "types", to see how well naturally deformed samples agree with the relationships predicted by experiments (e.g., Jung et al. 2006).

Bernard, R.E., Behr, W.M., Becker, T.W., and D.J. Young (in review) Relationships between olivine LPO and deformation parameters in naturally deformed rocks and implications for mantle seismic anisotropy. Submitted in 2019 to Geochemistry, Geophysics, Geosystems. Preprint posted to ESSOAr here: https://doi.org/10.1002/essoar.10500834.1

Bernard, R.E. and W.M Behr (2017) Fabric heterogeneity in the Mojave lower crust and lithospheric mantle in Southern California. JGR Solid Earth. DOI: 10.1002/2017JB014280


One tool I use to investigate the rheological properties of these rocks — and measure LPO — is Electron Backscattered Diffraction (EBSD). This tool allows for the identification of mineral phases based on their crystallographic structure, while also quantifying the orientations of those minerals. Below: (top) phase map of an awesome, highly deformed peridotite xenolith from Lunar Craters Volcanic Field in central Nevada; (bottom) the same mapped area, but with olivine colored based on orientation. This type of map allows us to investigate the grain elongation, subgrain development, and dynamic recrystallization preserved in this spectacularly deformed rock.