A ¹⁴C Calibration with AMS from 3500 to 3000 BC, Derived from A New High-Elevation Stone-Pine Tree-Ring Chronology

High-precision radiocarbon accelerator mass spectrometry (AMS) measurements of a new high-altitude stone-pine tree-ring chronology from the European Alps were performed for a 500-yr stretch in the second half of the 4th millennium BC. A 14 C calibration curve with a typical 1-σ uncertainty of about 20 14 C yr was achieved. Although the general agreement of our data set with INTCAL98 is very good (confirming once more that INTCAL98 is also proper for calibration of samples of extraordinary sites), we found small deviations of 17 ± 5 14 C yr, indicating possible seasonal effects of the delayed growing season at high altitude.