Short-term variability of sea ice and surface-water characteristic in the Late Neogene North Atlantic Ocean: A biomarker approach (IODP Leg 303 and 306)

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Understanding the mechanisms and causes of abrupt climate change is one of the major challenges in global climate change research today. In this context, the paramount importance of the North Atlantic as a possible major driver of global climate change has to be mentioned. Thus, new IODP Leg 303/306 sites were drilled at key locations in the North Atlantic to extend the present knowledge of millennialscale climate variability over the last few million years. These sites will give the unique possibility for detailed studies of organic carbon and biomarker records as tools for high-resolution reconstruction of sea-ice cover, sea-surface temperature, sea-surface salinity, and sea-surface productivity, to be done within this project. The project is composed of two subprojects especially focussing on two aspects. (1) The determination of paleosalinity records and their correlation with Heinrich Events and related IRD and meltwater pulses. Within IRD-/Heinrich-type intervals, specific terrigenous biomarkers indicative for IRD sources will be quantified. (2) The highresolution reconstruction of biomarker-based paleotemperature and its relationships to environmental change. Applied methods include elemental analyses (TOC, C/N), Rock-Eval pyrolysis, biomarker studies using GC and GC/MS techniques, and stable carbon isotopes of the organic matter and of specific biomarkers.