Rocks – Research Projects
Pressure-temperature-time evolution of metamorphic rocks in the Himalaya
In these collaborative projects primarily with Profs. D Robinson, Nadine McQuarrie, and Sean Long, we are determining P-T conditions and timing of metamorphism to better understand the tectonic evolution of the Himalaya. We have numerous samples from NW India, central and eastern Bhutan, and central Nepal. These span sub-garnet grade rocks of the Lesser Himalayan Sequence and the Tethyan Himalaya, to partially melted rocks of the Greater Himalayan Sequence. The metamorphic and chronologic evolution of these rocks has implications for tectonic models of the Himalaya, particularly whether the Greater Himalayan Sequence flowed (in a pipe-flow sense) towards the Indian foreland. Currently, graduate student Jesse Walters is working on these projects.
Titanite geochemistry and geochronology
Using our laser-ablation ICP-MS system, we discovered that Greater Himalayan titanite appears to preserve both its growth temperature (Zr thermometry) and age (U-Pb geochronology). Graduate student Jesse Walters is further exploring the utility of titanite for retrieving T-t paths in medium- to high-grade rocks.
Trace element thermometry and speedometry
The application of new trace element thermobarometers (e.g. Ti-in-zircon/quartz, Zr-in-sphene) require either the presence of rutile, or an estimate of the activity of rutile. We are investigating new methods of constraining parameters relevant to these systems (e.g. the activity of rutile in rocks that lack rutile, based on Ti equilibria), and in constraining element transport during cooling and its impacts on diffusion profiles. We work closely with Sarah Penniston-Dorland, at the University of Maryland, using rocks from Santa Catalina Island.
Subduction zone metamorphism and tectonics
In this ongoing project with Sarah Penniston-Dorland, we are determining P-T-t histories from the Santa Catalina Island subduction complex in southern California. This work involves close evaluation of trace element thermometers, as well as U-Pb geochronology. In addition, we are involved in a 5-year project to investigate Alpine subduction metamorphism under the auspices of the ExTerra (EXhumed TERRAnes) working group. In this project, called E-FIRE (ExTerra Field Institutes and Research Endeavor) we are collaborating with the ZIP (Zooming-In-between-Plates) consortium in Europe to constrain P-T-fluid-deformation evolution of the subduction interface. Boise State is leading this multi-million dollar, 9-institution project together with the University of Maryland (Sarah Penniston-Dorland) and Penn State University (Maureen Feineman).