High precision isotopic ratio measurements and trace and major element concentrations will be used to study fundamental processes of mantle differentiation and dynamical behavior. Our project addresses the timescales and trace element behavior associated with melt generation in the upper mantle, using coupled U-Th and Sm-Nd systematics in oceanic and continental basalts. A systematic data set will be assembled so that the competing effects of melt fraction and transport time can be evaluated. The ultimate objective is to improve the understanding of melt generation and trace element partitioning behavior, so that geochemical data can be more confidently applied in the study of solid earth geochemical cycles. A second project addresses the geochemical signatures of oceanic flood basalt provinces, using the Wrangellia Terrane basalts, to evaluate the relative contributions of plume heterogeneity, and lithosphere- asthenosphere contamination, on the isotopic signatures of plume-head volcanic products. The ultimate objective of the second study is to better constrain plume provenance, and thereby evaluate models for the evolution of the lowermost mantle. The research involves filed characterization of geological features, sampling, laboratory chemical and isotopic analysis, and the development of numerical process models to identify the controlling physical parameters and quantify the constraints imposed by the data base.
