First palaeomagnetic dating of ferricrete in New Caledonia: new insight on the morphogenesis and palaeoweathering of Grande Terre'

Abstract : Comparing palaeolatitudes estimated from remanent magnetization data of ferricrete developed over laterite at two sites (Goro and Tiebaghi) against the apparent polar wandering path of Australia provides new time constraints for the peridotite weathering in New Caledonia. The Tiebaghi Massif of the West Coast klippes displays a single episode of ferricrete development during latest Oligocene times. By contrast, the Goro site in the southern part of the Massif du Sud' reveals a more complex history with several episodes of ferricrete development from latest Oligocene to PlioceneQuaternary times. These data have made it possible to constrain the post-obduction geodynamics and associated morphogenesis of New Caledonia since related uplift probably prevented regolith development until latest Oligocene times. Moreover, the later uplift and deep erosion of the West Coast klippes during the Early Miocene probably prevented further regolith preservation.