Ocean circulation patterns especially within the deep ocean are a major player in global heat exchange and therefore force and stabilize climate patterns. In the North Atlantic, deep water masses are influenced by two main factors changing deep water strength and composition over time, the potential of water exchange with the Arctic Ocean and the development of the Northern hemisphere glaciation. The overflow across the Greenland-Iceland-Scotland Ridge, one of only two areas, where Arctic Ocean waters are exchanged with the world’s oceans, can be shut off by the periodically strong pulsation of the Iceland mantle plume or in more recent times by glaciation of the Northern Seas and its surrounding land masses.
In such an event, deep water circulation within the North Atlantic slows significantly, leading among other effects to a colder and more unstable climate in Western Europe.In this project, we propose to reconstruct the past behavior of deep water currents within the North Atlantic, by analyzing downhole logging data collected during IODP Expedition 395 "Reykjanes Ridge Mantle Convection and Climate". The drill sites are located in a transect along 60N, which represent a millennial scale archive of deep ocean sedimentation and current behavior ranging up to 12 Ma in the past to the Miocene. Downhole logging data will be collected after coring and has the advantages of being an in-situ continuous measurement through the strata, bridging potential gaps in core recovery. Recent experiments to measure current strength within the Atlantic has revealed, a decline in current strength in the recent past making the current circulation the weakest in the last millennia. Years of especially weak Atlantic currents correlate with an increase in weather events such as storms and floods within the British Isles and the rest of Western Europe. Understanding the past behavior of deep ocean circulation will therefore allow us to inform climate models used to predict severe weather events and use these predictions to minimize their impacts.