Modeling oxygen isotopes in ice sheets linked to quaternary ice-volume variations [Elektronische Ressource] / vorgelegt von Adriana Sima

Modeling oxygen isotopes in ice sheetslinked to Quaternary ice-volume variationsDissertation zur Erlangung des Doktorgrades der Naturwissenschaftenam Fachbereich Geowissenschaften der Universität Bremenvorgelegt von Adriana SIMABetreuung und 1. Gutachter: Prof. Dr. Michael Schulz 2. Gutachter: Prof. Dr. Johannes OerlemansEingereicht am 21.03.2005I want to know God's thoughts.The rest are details.Albert EinsteinAbstractClimate change through the Quaternary was dominated by the repeated build-up and retreat of largeice sheets in North America, northern Europe and some further places on the globe. The best18indicator for past variations of global ice volume is the isotopic composition O of seawater( ) recorded in foraminiferal calcite in marine sediments. Especially the benthic foraminiferalw18O ( ) has been long recognized as a very good proxy for and, hence, for ice volume. Butc wthe interpretation of benthic records in terms of ice-volume variations is not at allcstraightforward, mainly because depends not only on , but also on seawater temperature.c wFurthermore, even if the contributions of and temperature could be accurately disentangled,wother difficulties would arise. In common paleoceanographic practice the relationship between wand ice volume is considered linear, but two main factors have the potential to induce considerablenonlinearity.