Calibration Curve for Short-Lived Samples, 1900–3900 BC

Both the Pretoria and the Groningen radiocarbon laboratories performed high-precision analyses on 1–4 annual tree-ring samples made available by Bernd Becker from his South German oak dendrochronological series (Vogel et al. 1986; de Jong, Becker & Mook 1986). The Pretoria measurements were extended to overlap the Groningen set, and now cover the range from 1930 to 3350 BC (Vogel et al. 1993). The tree-ring dating of the Groningen samples has been adjusted and now ranges from 3200 to 3900 BC (de Jong, Mook & Becker 1989). Taken together, the data provide a calibration curve over two millennia, which is especially suitable for short-lived samples. The curve is shown in Figures 1A–D.