The last deglacial sea-level and climatic changes. Coral Reef records in the south Pacific : Tahiti (French Polynesia) - IODP Expedition #310 -, Australian Great Barrier Reef - IODP Proposal #519: Potential of diagenetically altered corals for sub-seasona

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The timing and course of the last deglaclation (23.000-6,000 calendar years BP - cal. yr BP) are essential components for understanding the dynamics of large Ice sheets and their effects on Earth's isostasy 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. This proposal Is related to the IODP proposal #519 concerning the coral reef records of Tahiti and the Australian Great Barrier Reef to establish the course of sea-level rise, climate variability and reef response during the last deglaciatton. It includes : 1) the study of more than 600 m of reef cores with an exceptional recovery that were retrieved from 37 holes ranging from 40 to 120 m water depth around Tahiti during the IODP Expedition 0310 « Tahiti Sea Level ». Distinctive levels of relict reefs covering most, if not all, the last deglaciation were drilled and therefore confirmed the significance of these features as unique archives of abrupt global sea-level rise and climate change. 2) Complimentary investigations of the Tahiti reef slopes, and 3) a site survey cruise on the Great Barrier Reef to generate high resolution bathymetric and seismic data that will be used to select suitable targets for an IODP drilling expedition corresponding to the part 2 of the IODP drilling proposal #519. The general scientific objectives of this proposal are threefold :a. To establish the course of post-glacial sea-level rise during the Last Deglaclation .b. To define SSTs and SSSs variations during the Last Deglaciation when solar insolation, sea level, and atmospheric CO2 levels were different from today. c. To analyze the impact of sea-level and environmental changes on reef development during the Last Deglaciation, with a special emphasis on the comprehensive reconstruction of environmental changes.