Improved Calibration of the Radiocarbon Time Scale

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This grant permits Dr. Stuiver, together with colleagues from other laboratories to conduct radiocarbon determinations on a series of German and Irish oak trees which date from between ca. 2500 and 5200 B.C. The absolute ages of tree rings within this sample are independently determined through the construction of an annual ring chronology which starts at the present and works back into the past. With these new determinations, Dr. Stuiver will construct a series of calibrations which will allow the accurate conversion of radiocarbon years into true age. Although the two are closely correlated they are not identical. Using this technique calibrations have been established from the present back to 2500 B.C. and this project will extend this by approximately another 2700 years. Because of the complicated relationship between "radiocarbon age" and "true age" sometimes materials with different true ages can give the same radiocarbon age. At some radiocarbon ages, the possible range of true ages can be smaller and at others larger. For archaeologists these discrepencies can be extremely important when comparisons are made from one culture area to another. For the more recent period Stuiver's calibration curve allows one to correct for this and it is important that this be extended further back in time. This research is important not only to archaeologists but to astronomers and geophysicists since the data provides information about changes in both solar radiation and in the earth's magnetic field.