CALIFORNIA INSTITUTE OF TECHNOLOGY
Explanations for why CO2 varies on glacial timescales and why the ice core records are out of sync on millennial-centennial timescales most likely reside in the deep ocean. To learn how we must first know how this reservoir changes under different climate states and across rapid climate transitions. Toward this objective the PIs outline a plan for using deep-sea corals to measure the past deep ocean temperatures and D14C. They will measure past D14C using combined U-series and 14C ages in a now
well-established deep-sea coral technique. They hope to measure past temperatures to 1 C or better using the newly established 'clumpy isotope' thermometer. As this technique depends on the relative ordering of 13C and 18O atoms in CaCO3 bonds, it is independent of the water d18O value. Samples are already in hand. Broader impacts include the support of the PhD work of an Indian-American scientist at Caltech.