A New εNd Record Covering Termination II

Monday, 15 December 2014: 10:50 AM
Emily Louise Deaney1, David J Thornalley2, Tina van de Flierdt3, Katharina Kreissig4 and Stephen Barker1, (1)Cardiff University, Cardiff, CF24, United Kingdom, (2)University College London, London, United Kingdom, (3)Imperial College London, London, SW7, United Kingdom, (4)Imperial College London, London, United Kingdom
The 143Nd/144Nd ratio (εNd) of seawater is used as a quasi-conservative tracer to examine past changes in water mass composition of the deep ocean. Records of εNd across the last deglaciation (Termination 1, T1) provide valuable information about water mass mixing that has improved our understanding of the ocean dynamics relevant to the process of deglaciation. However, questions remain concerning end-member source characteristics and regional hydrographic processes. Here we present a high resolution record of εNd derived from fish debris from ODP site 1063 across Termination 2. The different external and internal forcing (e.g. insolation versus freshwater) applicable to T2 make this a useful comparator for studies focused on T1. Accordingly we find large (up to 4 εNd units) fluctuations across T2 that can be related to high latitude climate changes as recorded by ice cores and other high resolution climate archives. We also identify periods of extremely negative values that require new explanations for changing end-member compositions. Our results have important implications for understanding North Atlantic deep water formation processes during critical climate transitions.