NA - Synchronizing Holocene Land-Ocean Climatic Records Utilizing Icelandic Tephra Horizons

The aim is to establish a transatlantic group of researcher to develop strong interdisiplinary research on refining the tephra chronology and testing of its utilty to study centennial and higher frequency climate variability in marine and terrestrial core archives. In order to obtain a better picture of the spatial pattern of centennial and higher frequency climate variability, precisely date records are required. Radiocarbon and most other dating tools lack the necessary precision. The evaulation of lead s and lags between changes in oceanic and/or atmospheric circulation and terrestrial response to such changes is vital in order to understand the forcing mechanisms behind these relatively high frequency climate oscillations. The most promising tool to sy nchronize these records is tephra geochemistry. In the northern North Atlantic region, Iceland serves as a source for more than 100 explosive emptions in the Holocene. Tephras from these eruptions are widely distributed in marine and terrestrial sediments as well as in glacial archives in the North Atlantic region. Based on their geochemical composition and stratigraphic positions, these tephras can be linked with eruptions events on Iceland and used as high precision correlation and both direct and indir ect dating tool for a number of high resolution climate archives from the region. In addition, these tephras can be used to determine the variability in time and space of the marine reservoir age in the North Atlantic region, and thus greatly improve the accuracy of the radiocarbon method on marine sediments in the region. We propose a to focus on the impacts of volcanism on the North Atlantic-Nordic Seas system, and to better utilize the time synchronization offered by diagnostic tephra from Icelandic sources. We will focus on three main componets: a) Marine circulation component, b) synchronization component and c) Limnological component.