Collisional Magmatism during the Amalgamation of Pangea: Implications for Crustal Growth Processes

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Continental crust covers almost 40% of the earth's surface and it is generally accepted that crustal growth has lasted from the early Archean to present-day. Traditionally, crustal growth was considered as accomplished primarily through island arc and continental arc magmatism with collisional orogenesis responsible for reworking of the continental crust. However, recent investigations of modern collisional orogens suggest that many magmatic rocks record depleted mantle isotopic signatures. This relationship suggests that continental subduction and collision zones may be key sites for the interaction and mass transfer between the crust and the mantle, the generation of juvenile magmas and the growth of continental crust. Magmatism occurs at different stages during the collisional process from continental subduction, exhumation to orogenic collapse, and much controversy still exists surrounding the (i) genesis of this magmatism, (ii) processes associated with crust and the mantle interaction, (iii) relationship of this magmatism to continental growth, and (iv) detailed evolution of the continental crust throughout earth's history.******In order to investigate these relationships, I will focus on the late Paleozoic Variscan orogen of Western Europe, which formed during the assembly, and amalgamation of the most recent supercontinent, Pangea. This well-documented collisional orogen provides exposure of a wide range of magmatic rocks, which formed at different stages of the continental collision and, therefore, provides an excellent framework to investigate crust-mantle processes and crustal growth during supercontinent amalgamation and, in turn, assess the role of late Paleozoic collisional magmatism to the global crustal evolution. ******The proposed research will focus on key locations around the Variscan orogen that each contains exposed magmatic rocks that formed at different times during the continental collision. My students and I will study the field relationships, age (U/Pb geochronology) and structural evolution of magmatic rocks to provide a space-time framework for the regional tectonic evolution. These observations and data will then be used to help interpret the geochemistry and isotopic signatures to assess how the interaction between the crust and mantle potentially changes with the evolving collision process.******This research is based solidly on my existing research strengths, and represents many undergraduate, graduate student and other HQP opportunities. The overall goal of my proposed program is to contribute to the understanding of the collisional magmatism during the Variscan Orogen, providing insight into the understanding of the genesis of orogenic magmatism, potential late Paleozoic crustal growth and the complex tectonics associated with supercontinent amalgamation.