The east Pacific island of New Caledonia, 2000 km NE of Sydney, Australia, hosts some of the world’s most abundant nickel deposits in one of the largest ophiolite bodies on Earth. The 300 km long ophiolite nappe represents a piece of oceanic lithosphere (mostly mantle) emplaced on a ribbon of continental crust in Eocene time. The ophiolite preserves a 15 km wide paleo-transform that is recognized in the field as a strike-slip shear zone in peridotite. This shear zone is best developed along the northern coast and is accessible by boat from the village of Ouassé. The shear zone has a 5 km wide core consisting of extremely deformed mantle. The paleo-transform may have developed near the ridge that formed the oceanic lithosphere.
Christian Teyssier’s group is studying mantle hydration in the New Caledonia paleo-transform shear zone. This work is in collaboration with Jessica Warren’s group (Stanford) and Mark Zimmerman (University of Minnesota). [photos by Christian Teyssier]