Land-ice teleconnections of cold climatic periods during the last Glacial/Interglacial transition

Climate Dynamics, Vol. 16, p. 229-239, 2000 

A. Brauer, C. Günter, J.F.W. Negendank
GeoForschungsZentrum Potsdam, Projektbereich 3.3 - Sedimente und Beckenbildung, Telegrafenberg, D-14473 Potsdam, Germany.
S.J. Johnsen
Departement of Geophysics, The Niels Bohr Institute of Astronomy, Physics and Geophysics, University of Copenhagen.

Independent calender year chronologies are a basic requirement for the establishment of high resolution land-ice teleconnections. The annually laminated Meerfelder Maar record provides both an independent chronology, established by varve counting, and high resolution lithological proxy data for the period of the last Glacial/Interglacial transition. These data reveal a series of four periods of climatic deterioration coinciding with negative isotopic deviations in the GRIP record signal, thus demonstrating the synchronicity of environment changes in Western Germany and temperature shifts in Greenland. The terrestrial data supports a further sub-division of the event stratigraphy based on the GRIP core, by introducing the cold event GI-1c2 between 13 500 and 13 400 calender years BP. Multiproxy analyses reveal that the environmental response at Meerfelder Maar was not linear throughout the Lateglacial but was modified by local processes. A change in the response of the lake environment to climate deterioration was observed during sub-stage GI-1b (Gerzensee oscillation), the only event with gradual rather than abrupt transitions. The two-fold character of the Younger Dryas as seen in the GRIP record is more pronounced in the Meerfelder Maar record. This lithological signal occurred with a delay of 60 years to the GRIP signal, and has been linked to a shift in the catchment. It is proposed that the trigger for this shift was a trend towards a more humid second half of the Younger Dryas.