Investigating North Atlantic Circulation During the Last Deglaciation.

As a component of the global ocean conveyor belt of heat, salt and nutrients, the Atlantic Meridional Overturning Circulation (AMOC) plays a major part in the global climate system. Sensitive to warming ocean temperatures and freshwater input from melting ice sheets and sea-ice and increased high-latitude precipitation, the stability of AMOC may be at risk in a warming world. Variations in AMOC have been linked with abrupt shifts between warm (interstadial) and cold (stadial) conditions in proxy records of the last 150,000 years, but the extent of any AMOC weakening and the associated mechanisms are not fully constrained. This project seeks to investigate changes in North Atlantic hydrography throughout the events observed in records of the last deglaciation (~19-11 ka: between the Last Glacial Maximum and the Holocene). This project will use a range of palaeoceanographic proxies including sortable silt, and oxygen isotope, clumped isotope and trace metal analyses in marine carbonates to reconstruct deep ocean flow speed and temperature at three depth-transects in the Northwest Atlantic. The generation of these Northwest Atlantic records will fill a gap in basin-wide proxy data coverage, thus facilitating an investigation in the relative phasing and regional differences in hydrography throughout the last deglaciation. Ultimately, this will increase our understanding of the mechanisms behind abrupt climate changes and provide a test-case scenario with which to evaluate climate model performance.