Grant: Discovery Grants Program - Individual

The long term objective of my research is to develop a better understanding of mountain building processes by investigating the architecture and the pressure-temperature-time (P-T-t) evolution of exposed orogenic cores. This proposal focuses on the metamorphic evolution and tectonic significance of granulites from two large orogens separated in time by ~1000 My: the deeply eroded Mesoproterozoic Grenville Province (central segment; Quebec) in which the orogenic core (hinterland) is widely exposed, and the modern Himalaya-Tibet system (Namche Barwa, eastern Himalayan syntaxis) in which exposure of core units is limited. Granulites are high temperature metamorphic rocks that typically occur in core zones of ""hot"" orogens and include pelitic rocks that have undergone substantial partial melting. The P-T-(t) evolution of such rocks is a direct response of thermal and tectonic processes operating in the orogenic crust. Recent developments in phase equilibria modeling, combined with careful examination of textures, allows for much improved determination of the P-T evolution of granulites, overcoming the limitations of traditional methods. The proposed approach involves: (a) geological mapping and sampling; (b) phase equilibria modeling of granulites to interpret textures and mineral chemistry in terms of P-T paths and deduce the tectonic environments of metamorphism ; (c) investigation of the textural setting and metamorphic reactions involving accessory minerals (apatite and monazite) that are relevant to P-T-(t) studies; (c) geochemistry and U-Pb geochronology to elucidate the nature of the original rocks that make up the hinterland of the central Grenville, their ages and the ages of metamorphism (in collaboration with others at MUN). The results will provide insights on the dynamics of middle to lower orogenic crust and on partial melting of crustal rocks in continental collision settings.