Temperature and Surface-Ocean Water Balance of the Mid-Holocene Tropical Western Pacific

Abstract
Skeletal Sr/Ca and 18 O/ 16 O ratios in corals from the Great Barrier Reef, Australia, indicate that the tropical ocean surface ∼5350 years ago was 1°C warmer and enriched in 18 O by 0.5 per mil relative to modern seawater. The results suggest that the temperature increase enhanced the evaporative enrichment of 18 O in seawater. Transport of part of the additional atmospheric water vapor to extratropical latitudes may have sustained the 18 O/ 16 O anomaly. The reduced glacial-Holocene shift in seawater 18 O/ 16 O ratio produced by the mid-Holocene 18 O enrichment may help to reconcile the different temperature histories for the last deglaciation given by coral Sr/Ca thermometry and foraminiferal oxygen-isotope records.