IODP Expedition 310 Reconstructs Sea Level, Climatic and Environmental chagnes in the South Pacific during the Last Deglaciation

Abstract

The timing and course of the last deglaciation (19,000–6,000 years BP) are essential components for understanding the dynamics of large ice sheets (Lindstrom and MacAyeal, 1993) and their effects on Earth’s isostasy (Nakada and Lambeck, 1989; Lambeck, 1993; Peltier, 1994), as well as the complex relationship between freshwater fluxes to the ocean, thermohaline circulation, and, hence, global climate during the Late Pleistocene and the Holocene. Moreover, the last deglaciation is generally seen as a possible analogue for the environmental changes and increased sea level that Earth may experience because of the greenhouse effect, related thermal expansion of oceans, and the melting of polar ice sheets.Corals are excellent sea level indicators and can be accu-rately dated; therefore, studying them helps in the determi-nation of the timing of deglaciation events and the under-standing of the mechanisms driving the glacial-interglacial cycles. Coral reefs are also sensitive recorders of past cli-matic and environmental changes. The skeletal geochemistry of annually-banded massive corals can provide a record of sea surface temperatures (SSTs) and salinities (SSSs). Because the amplitude of the last deglacial sea level rise was at least 120 m (Barbados: Fairbanks, 1989; Bonaparte Basin: Yokoyama et al., 2001; and review in Lambeck et al., 2002), the relevant reef and sediment archives are mostly found on modern fore-reef slopes where they can be investigated by dredging, submersible sampling, and coring. However, the scarcity of such cores and related data hinders our ability to unravel the rate and timing of the last deglacial sea level rise and prevents us from understanding the role of the Pacific Ocean as a climate modulator during the course of postgla-cial climate change.