Long-term tropical morphogenesis of New Caledonia (Southwest Pacific): Importance of positive epeirogeny and climate change

Extensive mapping of relict lateritic landsurfaces over the 1600 m of relief of mainland New Caledonia is used to evaluate long-term morphogenesis of the island since its emergence in the Oligocene. The results support the interpretation of the lateritic levels as abandoned, stepped remnant landsurfaces that may be grouped into eight island-scale erosion levels recording episodic lowering of base level. The separation of the erosion levels results from the combination of positive epeirogenic movements of the New Caledonia continental ridge and long-term Neogene climate variability, which is recorded by the contrasted erosion and weathering patterns of the three youngest levels and tentatively correlated with known global and regional paleoclimatic events.