Under this award the PIs will use fossil corals from the western Solomon Islands and eastern Papua New Guinea to reconstruct high-resolution Holocene/ Deglacial paleoclimate records. The study area is located near the heart of the Western Pacific Warm Pool (WPWP), a region that serves as the heat engine of the planetary climate system and a primary source of water vapor to the atmosphere. Studies of the instrumental record show that variations in the thermal and hydrologic properties of the WPWP have global ocean and atmospheric ramifications. This project would generate monthly resolved, multidecadal to century-scale proxy records of thermal and hydrologic variability in the WPWP via paired isotopic (?18O) and elemental ratio (Sr/Ca, Mg/Ca, U/Ca) determinations in fossil corals. These geochemical determinations will be made after the fossil coral samples have been evaluated for potential diagenetic alteration using petrography and mineralogy criteria and after they have been precisely dated by TIMS U-series analysis. The coral proxy climate records will be used to 1) identify and define the timing and magnitude of abrupt transitions and extremes in Holocene/Deglacial climate in the WPWP and determine how abrupt changes in the tropics are related to previously defined intervals of abrupt change in the extra-tropics; and 2) determine how changes in the mean climate state of the WPWP tropical region influence the nature of tropical climate variability on interannual to centennial timescales during the Holocene.
