Radiocarbon age of the Laacher See Tephra: 11,230+/-40 BP

The Laacher See Tephra (LST) layer provides a unique and invaluable time marker in European sediments with increasing importance because it occurs just before the onset of the Younger Dryas (YD) cold event. As the YD begins ca. 200 calendar years after the LST was deposited, accurate determination of the radiocarbon age of this ash layer will lead to a more accurate age assignment for the beginning of the YD. On the basis of 12 terrestrial plant macrofossil C-14 ages derived from sediments from Soppensee, Holzmaar and Schlakenmehrener Maar, we found an age of at least 11,230 +/- 40 BP for the LST event. This is ca. 200 yr older than the often reported age of 11,000 +/- 50 BP (van den Bogaard and Schmincke 1985).