Changes in North Atlantic deep water circulation, 3.3 - 3.0 Ma

• Main Authors: Khelifi, Nabil, Frank, Martin, Nürnberg, Dirk
• Format: Conference Object
• Language: unknown
• Published: 2011
• Subjects: Southern Ocean; North Atlantic Deep Water; North Atlantic; Northeast Atlantic
• Online Access: https://oceanrep.geomar.de/id/eprint/12457/

ABSTRACT FINAL ID: PP13B-1829 This study focuses on changes in the North Atlantic Meridional Overturning Circulation (MOC) and aims to provide a detailed reconstruction of intermediate to deep water mass distribution and circulation in the North Atlantic over the most recent Pliocene global warm period from ~3.3 to 3.0 million years ago (Ma). During that 300-kyr interval, the global temperature was ~3°C warmer than today, which is predicted to be reached before the end of this century due to the anthropogenic climate change. This warm period is therefore considered to be one of the closest and the most recent analogue for future global climate. It is thus uniquely suited for a case study with the goal to better understand the oceanographic and climatic processes controlling and responding to the global warming. Changes in deep circulation in the northeast Atlantic during the late Pliocene warm period were studied at a suite of IODP/ODP drill sites by using combined εNd, stable isotope, and Mg/Ca-based bottom water temperature records. First results show that the Southern Ocean Water may have influenced substantial volumes of the deep North Atlantic reaching depths as shallower as ~2400 m during that time. On longer timescale, a first significant re-organization of the deep circulation in the North Atlantic towards the modern conditions appears to start after ~1.5 Ma. – This study is currently under progress based on further core transects in the northern North Atlantic in order to better understand how water masses were distributed, how ocean circulation changed, and in which state the North Atlantic MOC was during this key period of past climate.