A high-resolution radiocarbon calibration between 11,700 and 12,400 calendar years BP derived from 230Th ages of corals from Espiritu Santo Island, Vanuatu

This paper presents radiocarbon results from a single Diploastrea heliopora coral from Vanuatu that lived during the Younger Dryas climatic episode, between ca. 11,700 and 12,400 calendar yr sp. The specimen has been independently dated with multiple Th-230 measurements to permit calibration of the C-14 time scale. Growth bands in the coral were used to identify individual years of growth. C-14 measurements were made on each year. These values were averaged to achieve decadal resolution for the C-14 calibration. The relative uncertainty of the decadal C-14 data was below 1% (2 sigma). The data are in good agreement with the existing dendrochronology and allow for hi,oh-resolution calibration for most years. Variations in the fine structure of the C-14 time series preserved in this specimen demonstrate sporadic rapid increases in the Delta(14)C content of the surface ocean and atmosphere. Certain sharp rises in Delta(14)C are coincident with gaps in coral growth evidenced by several hiatuses. These may be related to rapid climatic changes that occurred during the Younger Dryas. This is the first coral calibration with decadal resolution and the only such data set to extend beyond the dendrochronology-based C-14 calibration.