Transport, removal, and accummulation of sediments numerically simulated for paleo-oceans and reconstructed from cores of the eirik drift (TRANSPORTED)
The Eirik Drift south of Greenland records the changes in sediment transport by the deep ocean currents of the North Atlantic. The most influential bottom current is the Western Boundary Undercurrent (WBUC) which plays a major role in the global meridional overturning circulation and is driven by deep water formation in the Greenland, Labrador, Norwegian and Iceland Seas. Tectonic events and changing climate condi - tions have altered the pathway and strength of the WBUC over the last millions of years (Uenzelmann-Neben et al. (2016)). These changes are recorded in the sediments of Eirik Drift. By means of seismic profiles (e.g., Müller-Michaels and Uenzel - mann-Neben (2014, 2015)) and drill cores (Expedition 303 Sci - entists (2006), Shipboard Scientific Party (1987)), sedimentati - on rate and grain sizes can be determined since the late Miocene and the Pliocene. Both time slices have attracted interest of the climatological community due to their resemblance to possible future anthropogenically modified climate states (Salzmann et al. (2009)). Several numerical climate and ocean studies have linked local temperature and precipitation proxies to global climate changes during the late Miocene and the Pliocene. In the project TRANSPORTED we will link tectonic events and climate change to alterations of the strength and flowpaths of the WBUC and, hence, to sedimentation rates and grain sizes recorded in the cores from Sites 646 and U1305-1307 in the Eirik Drift. The numerical simulations will be carried out with the Re - gional Ocean Modeling System (ROMS, Shchepetkin and Mc - Williams (2005)). A regionalization to the North Atlantic enab - les us to simulate the areas of deep water formation in the North Atlantic and the Nordic Seas at unusually high spatial resolution and to resolve sediment transport by the WBUC in time and space. ROMS is a modern and highly modular ocean model code that uses terrain following sigma coordinates. The resul- ting higher resolution of oceanic bottom layers and the state of the art sediment and sea ice modules make ROMS a suitable choice for the proposed sensitivity simulations (cf., Li (2012)). This will lead to quantitative comparisons between simulated and reconstructed sediment transports at the Eirik Drift for the first time. Variations in sedimentation rate, sediment transport and grain sizes can be linked to climatic and tectonic events.