The Birnirk to Thule Transition as Viewed from Radiocarbon and Tree-Ring Dating within Two Adjacent Houses at Cape Espenberg, Northwest Alaska

The transformation of the Birnirk culture into the Thule culture is essential in reconstructing the emergence of modern Inuit across Alaska and the larger Bering Strait. To this end, two adjacent semi-subterranean houses of late Birnirk and early Thule affiliation, respectively, at the Rising Whale (KTZ-304) site at Cape Espenberg were recently excavated and dated by radiocarbon and tree-ring measurements. We present the Bayesian analysis of the resulting large series of dates, demonstrating the lack of contemporaneity between the two features: the Birnirk house was occupied in the late twelfth to early thirteenth centuries AD, whereas the occupation of the Thule house occurred in the second half of the thirteenth into the early fourteenth century. With the increased precision made possible by coupling dendrochronology with radiocarbon, our results place the Birnirk-Thule transition more that 200 years later than the generally accepted date of AD 1000. A transition in the second half of the thirteenth century has major implications for the timing of Thule presence along the coast of Alaska and for their migration into the Alaska interior. It aligns with a thirteenth-century migration into the western Canadian Arctic and farther east and a brief early or “initial” Thule period.