Evolution of mountain belts with an emphasis on shear zones and fold belts, currently focused on the southeastern New England Appalachians, the southern Abitibi Greenstone Belt of Ontario and Quebec, and the Idaho Springs - Ralston Shear Zone in Colorado. Structural analysis and geochronology of complexly deformed metamorphosed regions. Link between microstructures and growth of accessory minerals with tectonic motions and the evolution of mountain belts and (super)continents. Use of geochronologic methods to date deformation and investigate rates of deformation.