Dating and Digging Stratified Archaeology in Circumpolar North America: A View from Nunalleq, Southwestern Alaska

Abstract

ABSTRACT. Through the case study of the Thule-era village site of Nunalleq (GDN-248), this paper presents 14 C dating results and perspectives on the issues associated with radiocarbon dating stratified archaeological sites in circumpolar North America. The objective was to investigate relative variation in the 14 C age of ecofacts with the aim of establishing a hierarchy of dating suitability for Nunalleq that could more widely inform 14 C sample selection on archaeological sites across the North American sub-Arctic and Arctic and Greenland. Owing to the complexities associated with interpreting and establishing the relative chronology of the deeply stratified sod deposits at Nunalleq, we adopted open-area excavation and single-context recording methods. This approach, we suggest, allowed us to eliminate stratigraphic complexity as a source of variation in 14 C measurements and to assess the taphonomic issues associated with dating different ecofacts. In total, 16 samples were submitted for dating, comprising two sets of eight different ecofacts, one from each of two stratigraphically contemporary but spatially discrete contexts. In most instances, the 14 C ages of ecofacts were statistically indistinguishable between the two contexts and support the relative chronological relationships established by excavation. Only Elymus arenarius (grass) manufactures and Heleomyzidae (fly) puparia produced different ages in the two contexts, variations that suggest that these items are unreliable dating materials. As noted in previous studies, Phoca sp. (seal) and Oncorhynchus sp. (salmon) bone collagen demonstrated a strong marine reservoir effect (c. 700 14 C yr.). Picea sp. (wood chips) were marginally older than seeds from edible berries (Rubus chamaemorus and Empetrum nigrum) and caribou (Rangifer tarandus) bone collagen, which provided the most consistent ages.Key words: radiocarbon dating; single-context recording; Arctic; Alaska; Thule; archaeology RÉSUMÉ. Par le biais d'une étude portant sur le village de Nunalleq (GDN-248), appartenant à l'ère thuléenne, cet article présente les résultats de datations par le carbone 14 ainsi que les problèmes liés à la datation des sites archéologiques stratifiés situés dans la zone circumpolaire de l'Amérique du Nord. L'objectif consistait à examiner les variations relatives entre les âges C14 obtenus pour différents types d'écofacts, dans le but d'établir une hiérarchie pour Nunalleq qui pourrait plus largement informer la sélection de matériel à dater sur les sites archéologiques à l'échelle des régions subarctiques et arctiques de l'Amérique du Nord ainsi que du Groenland. Afin de faciliter l'interprétation et l'établissement d'une chronologie relative pour les dépôts de tourbe profondément stratifiés à Nunalleq, nous avons effectué des fouilles archéologiques à aire ouverte et adopté le « single context recording » comme système d'enregistrement. Nous suggérons que cela nous a permis d'éliminer la complexité stratigraphique comme source de variation dans les mesures de l'ac...

Stable Isotope Studies of North American Arctic Populations: A Review

“…Arneborg et al, 1999;Barrett & Richards, 2004;Craig, Bondioli, Fattore, Higham, & Hedges, 2013;Raghavan et al, 2014), local deviations, termed the delta (Δ) R, in the offset between atmospheric 14 C concentrations and the marine radiocarbon reservoir remain a major source of uncertainty that must be included in the calibration of 14 C ages from human and marine faunal skeletal remains (Bronk Ramsey, 2008;Stuiver, 1986). A discussion of ongoing research on this topic is beyond the scope of this paper, but readers are encouraged to see Dyke et al (2018), Krus, Jensen, Hamilton, and Sayle (2019), and Ledger, Forbes, Masson-MacLean, and Knecht (2016) for an Arctic perspective on this issue. In the following section, we elaborate on some of the issues associated with equifinality, and present recently developed areas of research that have potential applications in Arctic archaeology.…”

Three Generations Under One Roof? Bayesian Modeling of Radiocarbon Data From Nunalleq, Yukon-Kuskokwim Delta, Alaska

“…In 2015, further radiocarbon analyses (15 in total) were undertaken to examine inter-context 14 C age variation of a suite of ecofacts from the terminal occupation levels of Phase II. The results indicated that caribou ( Rangifer tarandus ) bone collagen and seeds from edible berries ( Rubus chamaemorus and Empetrum nigrum ) provided the most consistent age estimates (Ledger et al 2016). The work also confirmed previous observations regarding the MRE associated with bone collagen of marine organisms (e.g., Dumond and Griffin 2002), noted inconsistencies in the ages of grass artifacts, and highlighted wood at the site as being probable driftwood (Ledger et al 2016).…”

“…The results indicated that caribou ( Rangifer tarandus ) bone collagen and seeds from edible berries ( Rubus chamaemorus and Empetrum nigrum ) provided the most consistent age estimates (Ledger et al 2016). The work also confirmed previous observations regarding the MRE associated with bone collagen of marine organisms (e.g., Dumond and Griffin 2002), noted inconsistencies in the ages of grass artifacts, and highlighted wood at the site as being probable driftwood (Ledger et al 2016). Assays undertaken on wood, grass, and indeterminable plant remains have therefore been excluded from the current study.…”

“…Assays undertaken on wood, grass, and indeterminable plant remains have therefore been excluded from the current study. Details of the range finder dates are presented in Ledger and others (2016).…”

“…Myriad problems, arising both from the climate and lifeways practiced in northern regions, constrain the development of high-resolution chronologies in the Arctic (Ledger et al 2016) and the meaningful application of Bayesian methods. A preeminent issue is identifying samples on which to obtain accurate 14 C measurements.…”