On the Resolution of14C Dating Anomalies: Case Studies from New World Archaeology

We submit that anomalies in radiocarbon data in archaeological studies should be viewed positively as a stimulus to undertake further targeted research. Additional analyses to resolve anomalies have the potential to provide important insights into heretofore unstudied or incompletely understood depositional or geochemical processes affecting14C values, particularly in certain types of samples and samples from certain types of environments. We consider 2 major categories or sources of14C dating anomalies that we posit are mostly responsible for the vast majority of problematic14C results: anomalous sample contexts and anomalous sample composition. Two additional sources of14C anomalies are much more rarely encountered. Six case studies taken from New World archaeological studies are briefly presented to provide examples of where questions concerning the validity of14C measurements generated additional and ultimately more accurate understandings of temporal relationships. AMS-based14C measurement technology has rendered detailed investigations of14C anomalies routinely feasible.