Coral-based climate reconstructions from a massive Porites coral from a mid-Pacific shallowly submerged atoll: Sabine Bank (Vanuatu)

Sabine Bank (Republic of Vanuatu) is a carbonate bank that is rapidly subsiding (~1-2 mm yr-1) as it descends toward the New Hebrides Trench. Climatologically, Sabine Bank is located at the southern edge of the Western Pacific Warm Pool (WPWP) (≥28°C), and is well located to monitor ENSO- related climate variations in temperature and salinity. Previous work in the Vanuatu region has demonstrated that coral δ18O variability consistently correlates to the Niño-3.4 index. But more importantly, Sabine Bank offers perhaps the most purely open-ocean site from which a coral record has ever been developed. A modern, ~2.5 m long, massive Porites coral head was cored in ~12 m of water in 2006. Skeletal extension rates, estimated from banding discernable from X-radiographs is estimated at ~1.2 cm yr-1. A slab from this coral had has been sampled at ~monthly resolution and analyzed for Sr/Ca. The coral Sr/Ca record generated to date extends back ~70 yrs and exhibits a clear and pronounced climate signal. Coral δ18O determinations have been initiated. Eventually, we expect to have a >200 yr record of climate variability based on paired coral Sr/Ca and δ18O variations. Establishing such "proof of concept" with a modern coral at Sabine Bank is a prerequisite to proposed deep drilling at this location, whose tectonic setting offers a unique opportunity to sample fossil corals representing sea level and paleoclimate for a range of ages from MIS 7 to Present.