A New Radiocarbon Sequence from Lamanai, Belize: Two Bayesian Models from One of Mesoamerica's Most Enduring Sites

The ancient Maya community of Lamanai, Belize, is well known for its span of occupation from the Early Preclassic (before 1630 BC) to the present. Although most centers in the central and southern Maya Lowlands were abandoned during the Terminal Classic period (AD 750-1000), ceramic and stratigraphic evidence at Lamanai has shown continuous occupation from the start of the Early Preclassic to the Spanish Conquest. In this paper, we present the first complete set of radiocarbon dates from this important site, including 19 new accelerator mass spectrometry (AMS) ¹⁴C dates. We use these dates to build Bayesian models for a Terminal Classic structure and an Early Postclassic structure in the site center. This method assists in the refinement of older, conventional dates and provides key chronological information about the site during this volatile time. Adjustments to the standard, uniform distribution model are made using exponential, long-tail, and trapezoidal distributions to incorporate outlier samples and more accurately portray ceramic phases. Because of changes in construction behavior in the Terminal Classic, it is difficult to acquire primary samples from this period, but there remains enough overlap between dates and ceramic phases to deduce persistent occupation at Lamanai during the transition from Late Classic to Postclassic times.