Dendrochronology, 14C time-scale and mechanism of rapid climate change during the last deglaciation (TREE_14, FP14)

We propose to create an absolutely dated time frame, of annual resolution and accuracy, for the deglaciation and Late Glacial interval, based on dendrochronologically dated tree-ring chronologies. The extension will come from linking already existing, but floating, Late Glacial pine chronologies to the absolutely dated chronologies of the Hohenheim tree-ring labora-tory, using individual sections already filling the gaps, from undated pine sections already collected, and extensive new fieldwork, predominantly in South-eastern and Southern Europe. High-precision (±25 year) 14C analyses of decadal samples will extend the terrestrial 14C calibration into this crucial time interval, leading to a common time frame for important climate archives, dated by 14C. From the 14C data the fluctuations of the atmospheric 14C level is reconstructed, yielding information of solar variability and ocean ventilation changes. To separate solar, geomag-netic and oceanic forcing we use 10Be data from ice cores and geomagnetic intensity data, obtained in associated and ongoing projects. As 14C and 10Be fluctuations share a common cause (production changes) we can transfer the tree-ring time scale to ice-cores which will improve substantially the potential of ice cores as climate archives. Using well established climate proxies in tree-rings we will provide terrestrial climate information for the deglaciation and Late Glacial period.

Bernd Kromer*, University of Heidelberg, Heidelberg, DE

Svante Björck, Lund University, Lund, SE

Frédéric Guibal, Institut Méditerranéen d’Ecologie et Paléoécologie, Aix-en-Provence, FR

Barbara Wohlfarth, Stockholm University, Stockholm, SE

Jürg Beer#, EAWAG, Dübendorf, CH

Klaus Felix Kaiser#, Eidg. Forschungsanstalt für Wald, Schnee und Landschaft, Zürich, CH

Miklos Kazmer#, Eötvös University, Budapest, HU

Bogdan Onac#, Babes-Bolyai University, Cluj-Napoca, RO


* Project Leader
#Associated Partner