Collaborative Research: Temporal Evolution of Mantle Water: Quantifying the Effects of Recycling Efficiently Dehydrated Lithosphere into the Deep Mantle

University Of Miami, Coral Gables FL

Investigators

Abstract

Though all mantle plume basalts are wetter than MORB, recent work by the lead PI has shown that basalts associated with mantle plume components containing subducted lithosphere (EM-type) are less wet ("damp" plumes) than those associated with a common mantle or mildly-HIMU source (wet plumes). The likely explanation for this depletion is that water is efficiently extracted (>92%) from the lithosphere during the subduction process. Under this award the PIs will test and refine this hypothesis by (1) expanding the existing data sets to include H-, D-, and O-isotopes and Cl concentrations; (2) characterizing H2O, CO2, and Cl concentrations and stable isotopic compositions (H-, C-, and O-isotopes) of different mantle components as sampled by oceanic island and mid-oceanic ridge basalts (MORB) north of Iceland and within the Foundation Seamount Chain; and (3) developing box models to help understand the temporal evolution of water in the mantle, the origin of FOZO, and the regional heterogeneity in MORB water concentrations.