Spatial structure of the 8200 cal yr BP event in northern Europe

• Main Authors: Seppä, H., Birks, H. J. B., Giesecke, Thomas, Hammarlund, D., Alenius, T., Antonsson, K., Bjune, A. E., Heikkilä, M., Macdonald, G. M., Ojala, A. E. K., Telford, R. J., Veski, S.
• Other Authors: Department of Geology, Department of Biological Sciences Bergen (BIO / UiB), University of Bergen (UiB), Bjerknes Centre for Climate Research (BCCR), University of Bergen (UiB)-University of Bergen (UiB), Environmental Change Research Centre, University College of London London (UCL), Department of Geography, University of Liverpool, GeoBiosphere Science Centre, Quaternary Sciences, Geological Survey of Finland = Geologian tutkimuskeskus tuottaa (GKT), Department of Earth Sciences Uppsala, Uppsala University, University of California Los Angeles (UCLA), University of California (UC)-University of California (UC), Institute of Geology, Tallinn University of Technology (TTÜ)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2007
• Subjects: [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Arctic; North Atlantic
• Online Access: https://hal.archives-ouvertes.fr/hal-00298076; https://hal.archives-ouvertes.fr/hal-00298076/document; https://hal.archives-ouvertes.fr/hal-00298076/file/cp-3-225-2007.pdf

International audience A synthesis of well-dated high-resolution pollen records suggests a spatial structure in the 8200 cal yr BP event in northern Europe. The temperate, thermophilous tree taxa, especially Corylus , Ulmus , and Alnus , decline abruptly between 8300 and 8000 cal yr BP at most sites located south of 61° N, whereas there is no clear change in pollen values at the sites located in the North-European tree-line region. Pollen-based quantitative temperature reconstructions and several other, independent palaeoclimate proxies, such as lacustrine oxygen-isotope records, reflect the same pattern, with no detectable cooling in the sub-arctic region. The observed patterns challenges the general view of the wide-spread occurrence of the 8200 cal yr BP event in the North Atlantic region. An alternative explanation is that the cooling during the 8200 cal yr BP event took place mostly during the winter and spring, and the ecosystems in the south responded sensitively to the cooling during the onset of the growing season. In contrast, in the sub-arctic area, where the vegetation was still dormant and lakes ice-covered, the cold event is not reflected in pollen-based or lake-sediment-based records.