Investigating the tectonic evolution of the canadian cordillera through structural, metamorphic and multifaceted geochronologic studies

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The collision of continents, microcontinents, and island arcs at subduction zone boundaries is a fundamental mountain building process (i.e. orogenesis). The resultant geology of these mountain belts (orogens) includes a complex superposition of deformation and metamorphic events. My proposed research will focus upon investigating these interrelated tectonic processes associated with collisional orogens. In the Canadian Cordillera, my graduate students I and will continue to carry out a program of geologic mapping accompanied by microscope analysis in the lab of the structural and metamorphic elements. Another component of this research will include determination of precise timing constraints (geochronology) that are crucial for reconstructing the geologic history and developing tectonic models. Once the geologic relationships are rigorously determined via field-based mapping and microscope analysis, uranium (U) and lead (Pb) isotopes of radiogenic minerals (e.g. zircon, monazite) will be analyzed using a variety of geochronologic techniques. These include Isotope Dilution-Thermal Ionization Mass Spectrometry (ID-TIMS) and in situ analysis of minerals in thin section and grain mount using ion and electron microprobes and Laser Ablation-Inductively Coupled Mass Spectrometry (LA-ICPMS). My integrated approach to field geology and geochronology has proven to be very effective. I have provided highly precise and accurate age constraints for tectonic processes in the southern Canadian Cordillera, and have elucidated some of the complex crystal-chemical processes that plague radiometric minerals used for U-Pb geochronology. It is anticipated that the proposed research will refine our current understanding of tectonic processes associated with collisional orogens, and more specifically, the amalgamation and sculpting of the continental crust underlying the Canadian Cordillera.