Late Holocene Human Expansion Into Near And Remote Oceania: A Bayesian Model Of The Chronologies Of The Mariana Islands And Bismarck Archipelago

Since the investigations of Spoehr in the 1950s, most researchers have accepted a date of similar to 3500 BP/1500 BC for the initial human settlement of the Mariana Islands in the western Pacific. The relationship of this early expansion beyond Island Southeast Asia, characterized by Lapita-like pottery, to the appearance of Lapita in Near Oceania, generally was either given little thought or largely ignored. The Lapita settlement of Near Oceania is almost universally regarded as the initial expansion of Austronesian speakers into the Pacific, followed a few centuries later by a rapid migration to the east into Remote Oceania. More recently, however, radiocarbon evidence from several sites suggests that initial late Holocene expansion into the Pacific occurred in the Mariana Islands. This hypothesis needs critical evaluation. To this end, we created site- and region-level Bayesian calibration models. Results estimate that initial Lapita occupation of the Mussau Islands in the Bismarck Archipelago occurred between 3535 and 3234 cal BP (95% probability), which is 50-385 years (95% probability) earlier than the initial settlement of the Mariana Islands, dated to 3230-3085 cal BP (95% probability). Additionally, settlement of the Mariana Islands was either coeval or later (-66 to 254 years [95% probability]) than Lapita expansion out of Mussau into the greater Bismarck archipelago between 3397 and 3115 cal BP (95% probability). Radiocarbon datasets from these regions are hampered by problematic samples, and we anticipate that additional reliable radiocarbon dates will refine these estimates.