Occurrence of rhodolites in the tropical Pacific — a consequence of Mid-Miocene paleo-oceanographic change

Rhodolites occurring over wide areas of the tropical Pacific (Solomons, Loyalties, Vanuatu and Australes) are dated in many places by diagnostic larger foraminifera as of Middle Miocene age. They are preceded in Early Miocene and succeeded in Late Miocene by hermatypic coral deposits. The processes linking this facies change with time to paleo-oceanographic events documented in deep-sea sediments are identified as sea-level rise drowning the reefs, a slight drop of winter surface water temperature and an increase of the fertility of surface waters inhibiting compensatory growth of hermatypic corals until sea-level fall restored the earlier, original conditions of deposition.