Collaborative Research: Isotope Stage 3 Climate Change in the Western North Atlantic

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This proposal seeks support for a study of millennial scale climate events during marine isotope Stage 3 (~25 to 65 ka) from data in a depth transect of cores from the Blake-Bahama Outer Ridges. The project has two main objectives: (1) to test models of paleohydrographic change for Stage 3 events by making depth profiles in a limited geographic area, and (2) to investigate evidence for decade to century scale climate change in a Stage 3 time series from the Bermuda Rise. The first objective will test the model that massive discharges of icebergs, known as Heinrich events reduced production of both shallow and deep components of North Atlantic Deep Water, whereas more typical stadial events suppressed only the deep component. The second objective will investigate evidence for high-frequency oxygen isotopic oscillations in planktonic foraminifer from the Bermuda Rise. To put these results in a climatic context, we will develop the best possible age model for Stage 3 in the open ocean, and compare our new data to both existing alkenone-based temperature series and geochemical proxies for deep ocean ventilation changes.