AMS radiocarbon dating of annually laminated sediments from Lake Holzmaar

Abstract-- AMS radiocarbon ages have been determined on terrestrial macrotbssils selected from the annually laminated sediments of lake Holzmaar (Germany). The radiocarbon chronology of this lake covers the last 12.6 ka. Comparison of the radiocarbon dated varve chronology with tree ring data shows that an additional 878 years have to be added to the varve chronology. The correct-ed ~4C varve chronology of Holzmaar reaches back to ca. 13.8 ka cal. BP and compares favourably with the results from Soppensee (Switzerland) (Hajdas et al., 1993). The corrected ages for the onset and the end of the Younger Dryas biozone are 11,940 cal. BP and l 1,490 cal. BP, respective-ly. The ash layer of the Laacher See volcanic eruption is dated at 12,201 _+ 224 cal. BP and the Ulmener Tephra layer is dated at 10,904 cal. BP. QS