Paleo-environment and radiocarbon calibration as derived from Lateglacial/Early Holocene tree-ring chronologies

We present an overview of the extended Hohenheim oak chronology (HOC) and the dendrochronologically dated Preboreal pine tree-ring chronology (PPC). Both provide an absolute, annual time frame of the Holocene, extending into the Younger Dryas (YD) back to 11,919 BP. Two floating pine and larch chronologies are C-14 dated, covering large parts of the Lateglacial. Dendro-ecological parameters, such as ring width and stable isotope variation are used to infer past environmental conditions. C-14 analyses on decadal sections provide a high-precision, high-resolution data set for calibration of the radiocarbon time scale. Based on a marked change in ring-width and growth pattern, the YD termination is clearly identified in the German pine chronology. Its absolute age of 11,570 BP appears synchronous, within the errors of the respective chronologies, to related signals in the Greenland ice cores (GRIP, GISP2) and in lacustrine varve sequences. The C-14 age of the Laacher-See tephra (LST) is determined from a series of decadal tree-ring samples to 11,063 +/- 12 C-14 BP; the calibrated range is 13,010-13,200 cal BP. The climatic impact of the LST is reflected in the growth pattern of our tree ring chronologies. (C) 2000 Elsevier Science Ltd and INQUA. All rights reserved.