Bayesian Estimation Dating of Lithic Surface Collections

Surface assemblages represent the most accessible, representative sample of the archaeological record for the study of human socio-ecological systems at regional scales. However, the difficulty in developing suitable chronological frameworks from surface assemblages has limited their use. Additionally, surface scatters are composed of artifacts that can accumulate across multiple occupational episodes. A challenge to chronology building in such surface contexts is the necessity to assess the probability of occupation during each time period. We describe a new method of dating surface lithic assemblages using empirical Bayesian methods, with an example from northeastern Spain. We use Bayesian methods to estimate the probability of occupation during 11 temporal periods (ca. 13,000–4,200 cal BP) for a sample of 25 lithic surface assemblages. A Bayesian approach allows us to combine prior knowledge, with different degrees of uncertainty, about the temporal sensitivity of projectile forms statistically derived from a regional calibration data set of 35 dated assemblages to estimate the age of each surface collections probabilistically. This approach provides new insight into the settlement history of the Maestrat in the first half of the Holocene, during the transition from foraging to food production, and offers a powerful tool to archaeologists for the dating of surface collections.