Heidelberg 2015 – wissenschaftliches Programm
UP 13.22: Poster
Donnerstag, 26. März 2015, 10:45–19:45, G/Foyer
Deep Atlantic Circulation changes around Heinrich events: A 231Pa/230Th compilation — •Benny Antz1, Jörg Lippold2, Norbert Frank1, and Hartmut Schulz3 — 1Institute of Environmental Physics, University of Heidelberg, Germany — 2Institute of Geological Sciences, University of Bern, Switzerland — 3Department of Geosciences, University of Tübingen, Germany
Freshwater input through abrupt melting of continental ice sheets can affect the Atlantic Meridional Overturning Circulation's (AMOC) overturning vigour. Such forcing can be tested by investigating its behaviour during extreme iceberg discharge events into the open North Atlantic, so called Heinrich-Events [Heinrich 1988]. In this project we have measured 231Pa/230Th ratios in numerous sediment cores and present a compilation across Heinrich Events 1 (~17 ka BP) and 2 (~24 ka BP). The comparison of those demonstrates that interpretations of a single profile is not sufficient for reaching conclusions related to AMOC in its entirety. We observe large variations of opal contents and with a few data points showing correlation with 231Pa/230Th. Furthermore we find a clear disparity in the influence of melting icebergs on (North-) Atlantic Circulation during Heinrich Event 1 and 2. By the observation of self-measured and published 231Pa/230Th over Heinrich-Stadials 1 & 2 and their comparison we see, that a supposed weakening of AMOC strength due to freshwater-input was fiercer during Heinrich Stadial 1. With an inverse model approach [Luo et al. 2010] strength of the AMOC before, during and after the Heinrich-Stadials 1 & 2 will be derived from this database.