Eocene arc-continent collision in New Caledonia and implications for regional southwest Pacific tectonic evolution

New Caledonia preserves evidence that constrains models for the tectonic evolution of the southwest Pacific region. Onland geology reflects four main tectonic phases: (1) early Mesozoic development of subduction-related terranes and their accretion to the Gondwana margin; (2) Cretaceous passive margin development and sea-floor spreading during the Gondwana breakup; (3) foundering of an oceanic basin and the Eocene arrival of thinned Gondwana margin crust at a southwest-facing subduction zone, resulting in collisional orogensis and obduction of an ophiolitic nappe from the northeast; and (4) detachment faulting during extensional collapse, resulting in unroofing of metamorphic core complexes. -from Authors