Collaborative Research: Mantle Inputs to the Subduciton Factory: Assessing Scales of Spatial Variability Along and Across the IBM Converent Margin

Woods Hole Oceanographic Institution, Woods Hole MA

Investigators

Abstract

The objective of the project is to identify the mantle component in island arc volcanism by performing an across-arc study of magmatism in the southern Mariana Arc. The PIs propose to answer three principal questions using a field and laboratory study of submarine volcanoes in the Southern Seamount Province of the Mariana Arc. 1) Is the pattern of mantle depletion across the arc and the back-arc consistent with sequential melting of the mantle as it moves away from the back-arc spreading axis? 2) What is the inherent heterogeneity of the subarc mantle at scales of 10-60 km? 3) How are melts aggregated in arcs? They will answer these questions using a field program based on a high-resolution survey of two portions of the Southern Seamount Province, from the arc to the back-arc, using the Hawaii MR-1 towed vehicle; through detailed sampling of two traverses of the Province (including lavas and volcaniclastics); through characterization of the sampled materials petrographically and geochemically; and through interpretation of the data to identify the roles of along axis mantle heterogeneity.