Uplift rates of the Loyalty Islands as Determined by ²³⁰Th/²³⁴U Dating of Raised Coral Terraces

Uplift rates of the Loyalty Islands (S.W. Pacific) have been determined from 230 Th/ 234 U dating of raised coral terraces standing 2 to 7.5 m above sea level. The ages of the terraces on Ouvéa and Lifou correspond closely to previously documented periods of high sea levels at 120,000 and 180,000 yr BP. A +2-m terrace on Beautemps-Beaupré is considered to be beyond the range of the dating technique. The uplift rates of the various islands show a decrease toward the west. This lends support to the hypothesis of a lithospheric bulge of the leading edge of the Australian plate prior to its subduction at the level of the New Hebrides trench.