Dr. Chris Mattinson
My research interests center on using the evidence recorded in metamorphic rocks to address regional tectonic questions and to examine the time-scales of orogenic processes at convergent margins. In particular, my work with ultrahigh-pressure (UHP) rocks examines the behavior of the lithosphere during continental collision using metamorphic petrology, geochronology, geochemistry, and thermodynamics/thermobarometry. My main laboratory techniques are mineral chemistry by electron microprobe, U/Pb geochronology and trace element analyses by ion microprobe (SHRIMP-RG), and trace element analysis by laser ablation ICP-MS, coupled with evaluation of the geological context of the samples analyzed through field geology. My current and recent research projects include:
Ultrahigh-pressure metamorphism and geochonology, western China: One of the outstanding questions of ultrahigh-pressure metamorphism metamorphism is: How did these rocks return to the surface while preserving their high P/T mineral assemblages? Critical to addressing this question is a better understanding of exhumation rates from depths >80 km to the upper crust. These rates can be determined by combining geochronology and petrology, and therefore, I have focused on zircon U-Pb geochronology using the ion microprobe (SHRIMP-RG) linked to pressure, temperature, and mineral paragenesis by REE geochemistry, mineral inclusion analysis, and thermobarometry. Field work in the North Qaidam ultrahigh-pressure terrane in western China includes five field seasons in western China in 2001, 2002, 2008, and 2009. Graduate students: Brittany Fagin, Megan Regel, Ben Christensen.
Granulite facies metamorphism and geochonology, eastern Mojave, California: Granulites of the eastern Mojave record Early Proterozoic tectonism during the growth of the North American continent. This project uses field and petrographic investigation, combined with U/Pb geochronology of zircon and monazite, to address the timing of these events, and REE geochemistry, thin section and mineral inclusion relationships connect the U/Pb ages to metamorphic fabrics and mineral assemblages.
Fluid release in accretionary wedge metasediments, Olympic Peninsula, Washington: Field and petrographic investigation to constrain fluid volumes and fluid overpressure potentially related to seismicity. Graduate student: Holly Rotman.
Mineral separation yield efficiency and method development: This project evaluates the time and yield efficiency of heavy mineral separation using a spiral panner. Method development with a test sample of Mt. Stuart batholith granodiorite has improved the yield efficiency, and demonstrated spiral panning to be an effective method for small- to moderate-sized samples with typical zircon concentrations. Undergraduate researchers: Brittany Fagin, Ashley Edwards.