Palaeocene age for the Adio Limestone, New Caledonia: stratigraphic and regional context
Résumé
The Adio Limestone at the base of the Palaeogene flysch in the central part of New Caledonia has long been attributed to the Late Eocene. New data now enable us to assign it a Palaeocene age based on a characterisation of its benthic foraminiferal microfauna and also on the presence of an overlying sequence of typical calciturbidite dated as Early Eocene by its planktonic microfauna. This new age assignation indicates a major Palaeocene reorganisation of this northern part of the Norfolk Ridge, which can be associated with the beginning of the convergence phase and the onset of the northeast-dipping subduction in the oceanic South Loyalty Basin. The Adio area in this scenario would represent the initial expression of a foreland bulge uplifted in response to the onset of subduction to the northeast.