ABOUT RESOLUTION

Since Libby won the Nobel prize in 1960, radiocarbon (14C) became the worldwide used chronological framework. However, variations of the atmospheric 14C level result in differences between radiocarbon age and calendar age, which are resolved by linking 14C ages to an independently established time scale, a procedure called calibration.
Since 1993, the IntCal working group has been responsible for the creation of an internationally agreed calibration dataset, culminating in the most recent version, IntCal13. Although IntCal13 allows us to calibrate back to 50 ka BP, between 15 ka to 50 ka BP, the underlying low-resolution datasets differ up to 2000 years depending on the archive used (terrestrial and marine), instead of using only trees as was done for the past 14,000 years.With glacial trees, the calibration would be drastically improved, since trees have reliable annual rings and the cellulose is created directly from CO2 in the atmosphere. The second important point for the accuracy of the 14C ‘clock’ has to do with its error range, which always occurs with a 14C date. Taking the set of 14C data of a recently published Europe-wide study as a representative example, the error range of 14C dates at 42 ka 14C BP is usually well above ±1000 years.
Such a wide confidence interval, combined with the low resolution of IntCal in the Glacial, leaves substantial room for inaccuracies in absolute age estimates and ambiguities in chronological interpretation, creating competing scenarios and different hypotheses in human evolution.

- Objective 1: Create high-precision 14C datasets for glacial intervals from a collection of glacial trees found in sites in the Mediterranean and Southeast Europe

- Objective 2: Obtain near-absolute ages (ice-core timescale) of floating tree-ring chronologies using common signals in cosmogenic isotopes found in Greenland ice-cores. Reconstruction of solar variability

- Objective 3: Apply the secure and highly resolved 14C calibration to the study of human evolution
Reaching the first and second objectives will allow the team to reach confidence intervals of only a few centuries in the glacial time. We will obtain 14C errors of <±100 yr at 35 ka 14C BP, and <±300 yr at 42 ka 14C BP, using the most recent advances in AMS technique. This will have important implications for linking tree-ring climate records on ice core timescale, which will have impact for investigations of the role of climate events in human evolution.

The second and third objectives may point to another important result: Create a novel insight into the demise of Neanderthals and the spread of Anatomically Modern Human in Europe. Moreover, use tree-ring chronologies as proxies for solar variability to gain insight into solar variability in a time range, which is not yet accessible by any other approach, hence of high relevance for solar physicists.

Radiocarbon on Trees for the Objective 1

Dendrochronology for Objective 2

Radiocarbon on bones, charcoals and shells of MUP archeological sites for Objective 3