The principal investigator will study the origin of alkaline ring-dike complexes, and in particular the relationship between coexisting silica-undersaturated and silica-saturated syenites. Attention will be focused on the Red hill complex in New Hampshire, specifically on the mineral apatite, which as one of the first phases to crystallize most likely preserves information about the early history of these rocks. The relationship between rare earth element compositions of apatite in mafic enclaves to those in host syenites will be used as the primary investigative technique. The research will determine whether this approach is a useful one in establishing consanguinity between the enclaves and the host rocks, and may provide an important tool in investigating the very early stages of liquid descent in such rocks.
