Manufacturing continental crust in the subduction factory

Abstract

We are confi dent that ocean drilling at intra-oceanic arcs, such as the IBM, is the way to answer the fundamental question of how continental crust is created; to test the hypothesis of whether continents themselves are fi rst born in the ocean; and to understand the role of subduction-factory processes in solid Earth evolution. The key objective of this drilling effort is to sample rocks that form the deeper part of the arc crust, which is feasible only by riser drilling with Chikyu. To implement these IODP expeditions, pre-expedition, non-drilling efforts will be required, including acquisition of multichannel seismic refl ection and wide-angle seismic data for better imaging of the crust and upper mantle, heat fl ow measurements for confi rming the deep drilling, and petrological/chronological examination of seafl oor and on-land samples.