9802825 McNulty Subduction of the Nazca plate beneath South America has resulted in generation of the Andean continental magmatic arc, which often serves as the type locality of such arcs. However the interaction between plate relative motions, magmatic processes, and deformation are still poorly understood. This project takes advantage of a very young and well-exposed batholith in north-central Peru to address a variety of needed parameters such as age, depth of emplacement, wall and roof rocks and a marginal shear zone. Results will be integrated with extensive data on the batholith with the intent of formulating a general model for batholith emplacement in transtensional arc settings.