The archaeology of radiocarbon accelerator dating

Accelerator mass spectrometry (AMS) allows radiocarbon dating to be carried out by direct counting of¹⁴C atoms, rather than the conventional counting of radioactive disintegrations. The result is that samples up to 1000 times smaller can be handled. The approach was tested in principle by 1977 and for archaeological operation by 1983. More than 2000 samples per year are now being dated worldwide. The machines can now operate to about ± 80 years or better. Dates older than 40,000 years have not yet been achieved, but the ability to use small samples has already had considerable impact on dating the period 10,000–30,000 years ago. Bone is an ideal material for the new technique, since amino acids can normally be isolated and purified from gram-size samples. Studies of the origins of domestication are aided by the dating of individual grains and seeds. Because small samples can be mobile in the soil, careful sample selection strategies and procedures are required. The full impact of the technique can be assessed only through the rapid and comprehensive publication of archaeological results.     

Radiocarbon Chronology of the Siberian Paleolithic

We have compiled 462 C-14 determinations for 120 Paleolithic and Mesolithic sites from Siberia and the Russian Far East. The Mousterian sites are dated to ca. 46,000–28,500 BP. The Middle–Upper Paleolithic transition dates to ca. 43,300–28,500 BP. Although there are a few earlier sites, most of the Upper Paleolithic sites are dated to the time interval between ca. 34,000 BP and 10,000 BP. The earlier Upper Paleolithic stage is characterized by macroblade technology and is radiocarbon-dated to ca. 34,000–20,000 BP. The earliest microblade technology occurs in the late stage of the Upper Paleolithic, dated to ca. 23,000–20,000 BP, but the majority of microblade sites is dated to ca. 20,000–11,000 BP. The Final Paleolithic (Mesolithic) sites date to ca. 12,000–6000 BP. At ca. 13,000–11,000 BP, the earliest Neolithic appeared in both the Russian Far East (Amur River basin) and the Transbaikal. The Paleolithic–Neolithic transition occurred ca. 13,000–6000 BP.     

Contemplating the history and future of radiocarbon dating in the American Southeast

We consider the history, present, and future of radiocarbon dating in the American Southeast. We point out some of the past and present flaws related to archaeological research and dating. Our approach to this review is rooted in the perspective that each radiocarbon date collectively adds to our knowledge of the region and not just a particular site. Based on our observations, we suggest some “good” practices with respect to certain aspects of radiocarbon dating. Our concluding discussion considers Bayesian chronological analysis and the growing contribution of chronological modeling to the Southeast.     

The emergence of agropastoralism: Accelerated ecocultural change on the Andean altiplano, ∼3540–3120 cal BP

In the fourth millennium BP, there were major environmental and cultural changes on the Andean altiplano of South America, but the chronology remains vague. A recent synthesis describes a slow, gradual transition from hunting and gathering to agropastoralism. This proposal is tested by refining the date of the onset of more humid and stable conditions, around 3550 cal BP, based on a Bayesian model of 26 dates from Lake Wiñaymarka and an updated calculation of the lacustrine offset. This is compared to Bayesian models of 191 dates from 20 archaeological sites, which incorporate a number of recently processed radiocarbon dates. A synthesis is presented of 15 full coverage surveys, a summed probability distribution, and a Bayesian model of the transition to ceramics, which together support a scenario of a very rapid demographic increase. Fourteen models from archaeological sites are cross-referenced in a composite model, which identifies a brief, altiplano-wide emergence of agropastoralism with starting and ending boundaries of 3540 and 3120 cal BP, respectively. This starting boundary correlates strongly with the onset of improving environmental conditions, indicating synchronous cultural and environmental change. The suite of accelerating cultural changes included a marked reduction in mobility, a demographic surge, increased subsistence diversity, the adoption of ceramics, farming and the integration of camelid herding into a remarkably resilient economic strategy still in use today. This is a highly relevant but yet to be used comparative case study for the variable tempos of ‘big histories’, and ecocultural interactions that generate rapid, emergent episodes of wide-spread and enduring cultural change.     

A Spanish Man‐o‐War in New Zealand? The 1864 wreck of Grafton and its lessons for pre‐Cook shipwreck claims

This paper considers the 1864 wreck of Grafton in the Auckland Islands, and its implications for wreck analysis and pre‐Cook exploration claims. The captain of Grafton, Thomas Musgrave, stated that the schooner was built from the wreck of a Spanish man‐o‐war, and archaeological analysis of the wreck found that the timbers are a tropical South American species, and had possibly been reused. The implications of this are clear; it is possible that timbers that originated in pre‐Cook (1769) ships lie in New Zealand, but without a full understanding of the historical and archaeological context of any such timbers, including their reuse in later ships, it is not possible to claim proof of pre‐Cook European exploration of New Zealand.     

14C and Maya Long Count Dates: Using Bayesian Modelling to Develop Robust Site Chronologies

Bayesian statistics has now demonstrated its strong utility in archaeology, specifically through software that conditions radiocarbon data. Only recently has this technology been applied within Maya archaeology, however, in part because the Maya calendar provides a much greater resolution in dating archaeological events than is possible with radiocarbon data. The Long Count in particular allows for the assignment of some events relative to each other, accurate to the day. In this paper, a new approach is presented to incorporate robust records of both in the same Bayesian analysis through the OxCal software. The results do call for a reconsideration of the earliest radiocarbon studies in the Maya area from the 1960s, as well as the latest attempts to corroborate the currently popular calendar correlation known as the GMT. This new study demonstrates the value of the approach and corroborates the 1σ accuracy of the GMT, while at the same time opening up the possibility of revision by 20 or more years.     

The Comings and Goings of Sheep and Pottery in the Coastal Desert of Namaqualand,South Africa

This paper evaluates chronological trends in the presence and absence of domestic animal bone (sheep, goat, and cattle) and pottery in Namaqualand, the proposed gateway to the rest of South Africa for early herders or hunter-gatherers with sheep and ceramics. We update date calibrations with local ΔR corrections and mixtures of recent calibration curves and include five previously unpublished dates. We use histograms of calibrated medians, sorted in 100-year bins, to assess sustained regional patterns with dates associated with domestic animal bone and pottery (n = 73). While too small to be useful as a population proxy, the current set of dates does reveal three pulses of occupation separated by two clear gaps, which we evaluate with a Bayesian model of three sequential phases. The model's boundaries are used as estimates of the dates of Early (AD 80–210), Middle (AD 490–790), and Late (AD 1180–1690) occupational phases separated by two substantial lapses of 280 and 380 years, respectively. The alternating phases of presence and absence are suggestively correlated with climate shifts, leading to a discussion of the idea that effective moisture was a crucial factor in choosing whether to occupy Namaqualand. The set of archaeological dates has greater temporal and spatial resolution than many regional climate data, so we suggest that these trends may more accurately reflect the variable conditions specific to Namaqualand, at least until they are refined by future climate research.     

Recycled Blessings: An Investigative Case Study of a Rewrapped Egyptian Votive Mummy Using Novel and Established 3D Imaging Techniques

This case study was the first of its kind, where neutron computed tomography (CT) was applied to a wrapped mummified animal. Conventional X‐ray CT was also used to allow for meaningful comparison, and complementary data for a comprehensive investigation. Previous applications of both techniques are limited to metallic objects, such as bronze Buddhas. The mummy used in this study (IA.2402) is dated between the Third Intermediate Period (1069–664 bce ) to Late Period (664–332 bce ) according to the wrapping style, and was originally believed to contain a complete skeleton of a feline. However, precise date and provenance were unknown. Our results prove the presence of only partial juvenile feline remains, and provide a date range for artefact creation (900–804 bce ± 30) and alteration (367–204 bce ± 30). Therefore, this study implements an established imaging technique (neutron CT) in a novel way, while preserving and conserving the intrinsic value of the artefact through non‐destructive investigation.     

Radiocarbon dating of prehistoric hearths in alpine northern Sweden: problems and possibilities

The chronology of prehistoric Sami settlement sites has previously been established by conventional radiocarbon dating of bulk charcoal samples associated with hearths from sunken hut floors (stállo-foundations). Here we present results of a comprehensive dating exercise of stállo-foundations in the alpine area of northern Scandinavia using Accelerator Mass Spectrometry (AMS) radiocarbon dating of charcoal. Over a 3 km² study area, AMS calibrated ages of hearth charcoal from 22 stállo-foundations across 12 sites securely date these features to between cal. AD 640 and AD 1180. Only small variations in age were found between charcoal samples from different areas of a given hearth. Statistical analysis of all the charcoal AMS radiocarbon dates obtained reveals that 12 stállo-foundations across nine sites are contemporaneous and date to the Viking Period (AD 800–AD 1050). The tightly constrained AMS-based chronology of stállo-foundations contrasts with the existing chronology based on conventional radiocarbon analysis, which places these features within a significantly greater time-frame of between AD 600 and AD 1900, with most dates ranging between AD 800 and AD 1350.This discrepancy is likely to result from the necessity of collecting composite hearth charcoal particles, which may originate from different phases of occupation, in order to achieve the required final carbon content for conventional radiocarbon analysis. We argue that the new AMS-based radiocarbon chronology of stállo-foundations presented here supersedes the existing chronology based on conventional (Gas Proportional counting) radiocarbon analysis and we advocate the use of AMS radiocarbon dating in future hearth investigations.     

European Pond Turtles from Obříství (Bohemia,Czech Republic)

The paper describes and analyses recent finds of the European pond turtle (Emys orbicularis) from the archaeological sites at Obříství (Mělník District, at the confluence of the Elbe and Moldau rivers in the Bohemian Basin, Czech Republic). Turtle remains were found in three sunken features dated to the Late Bronze Age or to the Hallstatt period, and in one feature dated to the Neolithic. The high number of osteological finds, particularly the number of individuals found in one place, is unique within Bohemia and very rare for the Bronze Age to Iron Age in Europe. A large number of shell remains were identified, from at least 12 individuals in feature 1480, and from at least 5 individuals in feature 1483. The high numbers support the hypothesis that the European pond turtle was once a regular feature of the local fauna, even though the Bohemian basin is surrounded by mountains, which will have presented difficulties for the process of postglacial recolonization by semiaquatic thermophilous reptiles. The findings from Obříství show evidence of the exploitation of turtles for food. Signs of culinary procedures and the human consumption of turtles include anthropogenic chop marks, signs of burning and the apparently intentional segmentation of the turtle bodies. The quantity of turtle bones is still negligible, however, compared with those of mammals. Copyright © 2015 John Wiley & Sons, Ltd.