Last Interglacial coral record of enhanced insolation seasonality and seawater O-18 enrichment in the Ryukyu Islands, northwest Pacific

We present a calibrated, high-resolution O-18/O-16 and C-13/C-12 record for a well-preserved Last Interglacial Porites sp. coral (U-Th age of 127 +/- 6 ka) from the sea-level high-stand terrace of Yonaguni Island, Japan. Seas onal variations in the delta O-18 and delta C-13 values for the fossil cora l are greater than those observed in modem coral records from the same reef setting and appear to be driven by the enhanced insolation seasonality in the northern hemisphere during the Last Interglacial maximum. The O-18 enri chment of 1.1 parts per thousand in the fossil coral compared to the modem analogue cannot be due entirely to a reduction in sea-surface temperature b ecause corals in this region are already growing at their lower thermal lim it. Instead, most of the O-18 enrichment must be due to a change in the del ta O-18 of the surface seawater, probably in response to enhanced evaporati on of the ocean or a higher volume flux of the Kuroshio Current.