Reassessment of Some Radiocarbon Dates from the Central Plains

Radiocarbon dates from the Gakushuin Laboratory have been considered suspect for many years. In this paper, I compare the distribution of Gakushuin dates to those run at other laboratories, using a sample of 195 dates from sites of the Central Plains tradition. Simple inspection of the distribution of the two sets of dates shows that those from Gakushuin are very different than those from other laboratories, even when the samples come from the same sites. None of the Gakushuin dates can be considered reliable. The Gakushuin dates make up about one-sixth of the total number of Central Plains tradition radiocarbon assays. With their removal, it is possible to clarify the chronology of phases of the Central Plains tradition. It also forces reconsideration of earlier studies that relied on the Gakushuin dates.