Testing the Dicarb problem: A case study from North Alaska

An assumption exists in North Alaskan archaeological literature that radiometric assays produced by the now defunct Dicarb Radioisotope Co. (Dicarb) are too young or more recent when compared to those produced by other laboratories. This assumption is statistically tested by comparing radiocarbon assays produced by Dicarb to those produced by Beta Analytic, Inc.; Geochron Laboratories; and the NSF-Arizona AMS Facility. The primary data set consists of radiometric and accelerator mass spectrometry (AMS) assays produced from materials excavated at the Croxton site, Locality J, Tukuto Lake, northern Alaska. Statistical analyses demonstrate that C-14 assays produced by Dicarb tend to be younger than assays produced by other laboratories on crosscheck samples, with differences ranging between 350 and 1440 yr.