Noble Gases, Lower Mantle Structures, and the Origin of Ocean Island Basalts

Williams Curtis D, Tempe AZ

Investigators

Abstract

Dr. Curtis Williams has been awarded an NSF EAR Postdoctoral fellowship to carry out a research and broadening participation plan at the University of California - Davis. The investigator will determine noble gas systematics and develop models of mantle convection to better constrain the formation, location, and preservation of the source region for mantle plumes. Ocean island basalts (OIBs) represent the surface manifestation of plumes that originate in the lower mantle; as such, OIBs provide valuable information regarding chemical structure and dynamics of Earth's lower mantle. The study of noble gases in OIBs is crucial to the understanding of the chemical composition and structure of Earth's lower mantle, the understanding of Earth's accretion, its subsequent differentiation and degassing, and the formation of the atmosphere. Dr. Williams will contribute to the training of the next generation of Earth scientists by being a role model and engaging students from under-represented groups. This investigation will use noble gas systematics of OIBs to: [1] constrain the source region of the primitive noble gases in the lower mantle; [2] document the heavy noble gas signature of enriched mantle components and understand the genetic relationship between the different components as determined from the noble gases; [3] use dynamic models of mantle convection to understand the preservation of chemical heterogeneities and whether the degree of entrainment of a dense basal layer in the lower mantle is consistent with geochemical observations in mantle plumes.