High-Precision 14C Measurement of Irish Oaks to Show the Natural 14C Variations from 200 BC to 4000 BC

Abstract

Bi-decade samples of dendrochronologically matched Irish Oak, measured with a precision of ca ± 20 years, covering the period 200 to 4000 BC are presented. The data are compared with the published data of Suess, de Jong, and Mook to provide a general calibration of the 14C time scale for this period. Although the dendrochronologic sequences presented are not absolutely tied to present, the best fit (based on 14C evidence) of the Belfast data to absolute chronologies, the error and evidence associated with such positioning is given. The intervals chosen for analysis were 20 years, reducing slightly the resolution of short-term variations when compared to 10-year intervals, which are sometimes measured. However, this calibration would suffice for most scientific purposes and certainly for the calendrical conversion of 14C dates derived from archaeologic samples.