C04_05

Towards a continuous, annually resolved tree-ring record spanning the past 6000 years

Wacker L¹,  Brehm N¹, Christl M¹, Synal H¹, Bayliss A², Nicolussi K³, Pearson C⁴, Bleicher N⁵, Brown D⁶, Bollhalder S¹, Alter M¹

¹Laboratory of Ion Beam Physics, ETH Zurich, Zürich, Switzerland, ²Historic England, London, Great Britain, ³Universität Innsbruck, Innsbruck, Austria, ⁴University of Arizona, Tucson, USA, ⁵Underwater archaeology and Dendroarchaeology Zurich, Zürich, Switzerland, ⁶The Queen's University, Belfast, Great Britain

As a consequence of the instrumental progresses combined with more efficient sample preparation, IntCal20 contains now 5 000 new AMS measurements in addition to 1 000 decay measurements on annually resolved tree-rings of the previous IntCal iteration (IntCal13). It is primarily this new annually resolved data, that nearly doubled the dataset, on which IntCal20 is  based today. Still, the significantly increased resolution of IntCal20 can be considered just as the start for a more detailed (spatio-) temporal mapping of past atmospheric radiocarbon concentrations. Only 20% of the last 14 000 years available at annual resolution are yet measured, while the rest is only available at decadal or lower resolution.

We will present an update on our efforts to measure the hole tree-ring based part of IntCal  annual resolution. We present more than 3 000 new annually resolved ¹⁴C measurements performed on tree-ring samples covering the last 6 000 years. A thorough analysis of reproducibility will be presented and  possible reginal offsets will be discussed. The new data represents a significant progress  towards  an enhanced high-resolution calibration curve.