Radiocarbon calibration

The radiocarbon dating method was originally thought to be an absolute dating method for organic material, that means that it is possible to determine the age of an organic sample by simply measuring its 14
ratio. However, later investigations showed that things are not that easy and that some kind of calibration is necessary to give appropriate dates. For the Holocene (the current interglacial warm period, i.e. the last 12.000 years) dendrochronologically dated long tree-ring sequences are used for calibration. Therefore it is important that the dendrochronology of these sequences is correct, otherwise also the radiocarbon calibration curve would be in error.

As we suspect large errors in the long European oak chronologies which have been used to build the terrestrial radiocarbon calibration curve commonly in use (IntCal13), we have scanned the available data for inconsistencies regarding the dendrochronology. The result is summarized in our appended Excel workbook (see below).

The first sheet focuses on the Pearson calibration (1986, Irish oak), while the second sheet contains the remaining single measurements on Irish oak. The third sheet contains the Suess calibration (1978, bristle cone pine). These data are visually compared in Diagrams 1 and 3.

The fourth sheet contains data for the Seattle calibration (1986, German oak) which is compared visually with the Pearson calibration in Diagram 2.

The fifth sheet contains data of the absolute Torneträsk pine chronology (2002), which is visually compared with the Suess calibration in Diagram 4, and with the Pearson calibration in Diagram 5.

Our comments are included in the sheets.


(About year count and notation read explanation here, opens in new tab)