Improved Calibration of the Radiocarbon Time Scale

这笔拨款允许斯图弗博士与其他实验室的同事一起，对大约公元前2500年至公元前5200年之间的一系列德国和爱尔兰橡树进行放射性碳测定。该样本中树木年轮的绝对年龄是通过构建年轮年表独立确定的，年轮年表从现在开始，一直追溯到过去。有了这些新的测定，斯蒂弗博士将建立一系列的校准方法，将放射性碳年精确地转换为真实年龄。虽然两者密切相关，但并不完全相同。使用这种技术，校准已经从现在追溯到公元前2500年，这个项目将把它延长大约2700年。由于“放射性碳年龄”与“真实年龄”之间的复杂关系，有时不同真实年龄的材料可以给出相同的放射性碳年龄。在某些放射性碳年代，真实年龄的可能范围可能小一些，而在另一些年代则可能大一些。对于考古学家来说，当比较一个文化区域与另一个文化区域时，这些差异可能是极其重要的。对于最近的一段时间，斯图弗的校准曲线允许人们对此进行校正，重要的是将其进一步扩展到过去。这项研究不仅对考古学家很重要，而且对天文学家和地球物理学家也很重要，因为这些数据提供了有关太阳辐射和地球磁场变化的信息。

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.