Radiocarbon Dating as a Probabilistic Technique: The Childers Site and Late Woodland Occupation in the Ohio Valley

1992 ◽  
Vol 57 (2) ◽  
pp. 202-230 ◽  
Author(s):  
Michael J. Shott

Like any scientific technique, radiocarbon dating has limitations, and its results cannot be interpreted uncritically. The archaeological record of Childers, a Late Woodland site in eastern North America, and inferences concerning its occupational history are evaluated here against radiocarbon dates from the site. The record suggests a single, relatively brief, occupation, but radiocarbon-dating results suggest either a much longer continuous occupation or a long series of shorter ones. The apparent conflict between the archaeological record and radiocarbon results is resolved by considering context and integrity of radiocarbon samples, as well as the probabilistic character of the radiocarbon method itself. Considerable dispersion in dating results can occur even in relatively brief occupations, casting doubt on the uncritical interpretation of raw radiocarbon results. Childers's occupational history and chronological placement have important implications for regional culture process during the early Late Woodland interval, and suggest a time lag in the acceptance of cultural innovations.

2003 ◽  
Vol 68 (4) ◽  
pp. 719-735 ◽  
Author(s):  
William C. Prentiss ◽  
Michael Lenert ◽  
Thomas A. Foor ◽  
Nathan B. Goodale ◽  
Trinity Schlegel

This paper provides an analysis of radiocarbon dates acquired during earlier and recent field seasons at the Keatley Creek site, southern British Columbia. Results indicate that early occupations predating 1900 cal. B.P. occurred, but were not likely associated with population aggregation and large housepits. The aggregated village appears to have emerged by approximately 1700 cal. B.P. and was abandoned at approximately 800 cal. B.P. A break in the occupational sequence is recognized at 1450-1350 cal. B.P. and one other short break may have occurred shortly after 1250 cal. B.P. Peak socioeconomic complexity appears to have been achieved between 1350 and 800 cal B.P. Climatic warming may have provided a selective environment favoring population aggregation and intensification during this time. The final abandonment of the Keatley Creek village appears to have been part of a regional phenomenon suggesting the possibility that climatic factors were important in this case as well.


2016 ◽  
Vol 13 (5) ◽  
pp. 1537-1552 ◽  
Author(s):  
Marta Petrillo ◽  
Paolo Cherubini ◽  
Giulia Fravolini ◽  
Marco Marchetti ◽  
Judith Ascher-Jenull ◽  
...  

Abstract. Due to the large size (e.g. sections of tree trunks) and highly heterogeneous spatial distribution of deadwood, the timescales involved in the coarse woody debris (CWD) decay of Picea abies (L.) Karst. and Larix decidua Mill. in Alpine forests are largely unknown. We investigated the CWD decay dynamics in an Alpine valley in Italy using the chronosequence approach and the five-decay class system that is based on a macromorphological assessment. For the decay classes 1–3, most of the dendrochronological samples were cross-dated to assess the time that had elapsed since tree death, but for decay classes 4 and 5 (poorly preserved tree rings) radiocarbon dating was used. In addition, density, cellulose, and lignin data were measured for the dated CWD. The decay rate constants for spruce and larch were estimated on the basis of the density loss using a single negative exponential model, a regression approach, and the stage-based matrix model. In the decay classes 1–3, the ages of the CWD were similar and varied between 1 and 54 years for spruce and 3 and 40 years for larch, with no significant differences between the classes; classes 1–3 are therefore not indicative of deadwood age. This seems to be due to a time lag between the death of a standing tree and its contact with the soil. We found distinct tree-species-specific differences in decay classes 4 and 5, with larch CWD reaching an average age of 210 years in class 5 and spruce only 77 years. The mean CWD rate constants were estimated to be in the range 0.018 to 0.022 y−1 for spruce and to about 0.012 y−1 for larch. Snapshot sampling (chronosequences) may overestimate the age and mean residence time of CWD. No sampling bias was, however, detectable using the stage-based matrix model. Cellulose and lignin time trends could be derived on the basis of the ages of the CWD. The half-lives for cellulose were 21 years for spruce and 50 years for larch. The half-life of lignin is considerably higher and may be more than 100 years in larch CWD. Consequently, the decay of Picea abies and Larix decidua is very low. Several uncertainties, however, remain: 14C dating of CWD from decay classes 4 and 5 and having a pre-bomb age is often difficult (large age range due to methodological constraints) and fall rates of both European larch and Norway spruce are missing.


Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 103-110 ◽  
Author(s):  
Anna Pazdur ◽  
Mieczysław F. Pazdur ◽  
Jacek Pawlyta ◽  
Andrzej Górny ◽  
Michał Olszewski

We report preliminary results of a long-term systematic study intended to gather paleoclimatic records from precisely dated speleothems. The research project is limited to speleothems deposited in caves of the Cracow-Wieluń Upland, the largest and best-explored karst region in Poland, covering ca. 2900 km2 with >1000 caves. Speleothem samples were selected from collections of the Geological Museum of the Academy of Mining and Metallurgy in Cracow. Radiocarbon dates of these samples from ca. 45–20 ka bp almost exactly coincide with age range of the Interplenivistulian. A break in speleothem formation between ca. 20 and 10 ka bp may be interpreted as a result of serious climatic deterioration associated with the maximum extent of the last glaciation. We observed differences among 14C, U/Th and AAR dating results. Changes of δ13C and δ18O in speleothems that grew between ca. 30 and 20 ka bp may be interpreted as changes of paleoclimatic conditions.


2002 ◽  
Vol 33 ◽  
pp. 9-19 ◽  
Author(s):  
David Mattingly ◽  
David Edwards ◽  
John Dore

AbstractThis short paper presents a full list of the currently available radiocarbon dates from the work of Charles Daniels in the 1960s-1970s and the Fazzan Project (1997-2001). The dates can be grouped into several categories, by site or area, and demonstrate the potential of radiocarbon dating being applied to historic-period archaeology in the Sahara. This complements earlier Italian work on later prehistory. One of the most important conclusions to emerge is that the construction of castle-like buildings in Fazzan began within the Garamantian period and that some of the numerous well-preserved mudbrick fortified sites are thus rather earlier than has previously been envisaged. A second important conclusion is that the use of AMS dating can help to identify and confirm activity of the post-Garamantian and early Islamic phases, which has hitherto been elusive.


Radiocarbon ◽  
1983 ◽  
Vol 25 (2) ◽  
pp. 639-644 ◽  
Author(s):  
H T Waterbolk

In the past 30 years many hundreds of archaeologic samples have been dated by radiocarbon laboratories. Yet, one cannot say that 14C dating is fully integrated into archaeology. For many archaeologists, a 14C date is an outside expertise, for which they are grateful, when it provides the answer to an otherwise insoluble chronologic problem and when it falls within the expected time range. But if a 14C date contradicts other chronologic evidence, they often find the ‘solution’ inexplicable. Some archaeologists are so impressed by the new method, that they neglect the other evidence; others simply reject problematic 14C dates as archaeologically unacceptable. Frequently, excavation reports are provided with an appendix listing the relevant 14C dates with little or no discussion of their implication. It is rare, indeed, to see in archaeologic reports a careful weighing of the various types of chronologic evidence. Yet, this is precisely what the archaeologist is accustomed to do with the evidence from his traditional methods for building up a chronology: typology and stratigraphy. Why should he not be able to include radiocarbon dates in the same way in his considerations?


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7174
Author(s):  
John P. Hart ◽  
Robert S. Feranec ◽  
Timothy J. Abel ◽  
Jessica L. Vavrasek

Isotopic analysis of dog (Canis lupus familiaris) bone recovered from archaeological sites as proxies for human bone is becoming common in North America. Chronological placement of the dogs is often determined through radiocarbon dating of dog bone. The Great Lakes, their tributaries, and nearby lakes and streams were important fisheries for Native Americans prior to and after sustained European presence in the region. Carbon entering the food web in freshwater systems is often not in full isotopic equilibrium with the atmosphere, giving rise to spuriously old radiocarbon ages in fish, other aquatic organisms, and their consumers. These freshwater reservoir offsets (FROs) have been noted on human and dog bone in several areas of the world. Here we report the results of multi-tracer Bayesian dietary modeling using δ15N and δ13C values on dog bone collagen from mid-fifteenth to mid-sixteenth-century Iroquoian village sites at the headwaters of the St. Lawrence River, New York, USA. Results indicate that fish was an important component of dog diets. A comparison of radiocarbon dates on dog bone with dates on deer bone or maize from the same sites indicate FROs ranging from 97 ± 24 to 220 ± 39 14Cyr with a weighted mean of 132 ± 8 14Cyr. These results suggest that dog bone should not be used for radiocarbon dating in the absence of modeling to determine fish consumption and that previously reported radiocarbon dates on human bone from the larger region are likely to have FROs given the known importance of fish in regional human diets.


1975 ◽  
Vol 41 ◽  
pp. 179-182 ◽  
Author(s):  
Andrew B. Smith

In 1940 Professor Thurstan Shaw excavated a trench in the cave known as Bosumpra at Abetifi (6° 41′N:0° 44′W) on the borderline between the moist forest and the northern marginal forest (fig. 1). Bosumpra is one of the four main ‘abosom’ (lesser) gods of the Guan pantheon (Brokenshaw 1966, 156). The report (Shaw, 1944) showed that the cave was formerly inhabited by a people with a pottery-using microlithic culture and provided the first analytical description of the microlithic industries from the forest regions of West Africa. As the site was the first of its kind to be excavated, and the excavation was carried out before the advent of radiocarbon dating, there was no way of knowing what age this industry was, or how long the cave had been occupied, beyond placing it within the rubric of the so-called “Guinea Neolithic”.To attempt to clarify this problem a group of students from the Department of Archaeology at the University of Ghana and myself conducted the excavation of a small witness section (fig. 2) in the cave over New Year 1973/74 with the specific aim of collecting organic material for dating. We were fortunate in finding adequate amounts of charcoal at all levels. Two of these samples were submitted to Rikagaku Kenkyusho, Japan, for dating.


Radiocarbon ◽  
2014 ◽  
Vol 56 (1) ◽  
pp. 295-303 ◽  
Author(s):  
David V Burley ◽  
Kevan Edinborough

The Fijian archaeological record is segmented into a series of phases based on distinctive transformations in ceramic forms. Interpretations of the mid-sequence (∼1500–1300 cal BP) transition between the Fijian Plainware phase and the Navatu phase are contentious, with alternative explanations of population replacement versus internal processes of culture change. We present and analyze a series of Fijian Plainware and Navatu phase AMS radiocarbon dates acquired from superimposed but stratigraphically separated occupation floors at the Sigatoka Sand Dunes site on the southwest coast of Viti Levu. Employing an OxCal Bayesian sequential model, we seek to date the temporal span for each occupation as well as the interval of time occurring between occupation floors. The latter is estimated to be 0–43 calendar years at 2σ probability. The magnitude of ceramic and other differences between the Fijian Plainware and Navatu phase occupations at Sigatoka is substantive. We conclude that the abruptness of this change can be explained only by exogenous replacement at the Sigatoka site.


2021 ◽  
Author(s):  
◽  
Rimpy Kinger

<p>Burnt or fired archaeological artefacts often retain a record of the magnetic field in which they were last heated and cooled. Over the past four years we have collected oriented hangi stones from 10 archaeological sites spread across the North and South Islands of New Zealand. The stones vary in lithology from andesites, originating from the central North Island volcanoes, favoured by Maori for their durability and with remanent magnetization up to 30 A/m, to sandstones and schists from the main axial ranges, with magnetizations as weak as 10-4 A/m. Radiocarbon dating of charcoal fragments retrieved from amongst the stones indicates that the sites span from ca. 1400 AD to the present.  In all cases, we have independently oriented and retrieved several stones, and we have made several samples from each stone, either by drilling (standard cylindrical samples) or sawing (pseudo-cubes) in the laboratory. We have calculated site mean palaeomagnetic directions (Dec between 1.5o and 19.6o and Inc between -52.2o and -68.3o) from principal component analysis of thermal demagnetization and alternating field demagnetization data, discarding the data of stones that show evidence of disturbance after cooling. The directions are in good agreement with recently published palaeosecular variation records from lake sediments. We have carried out palaeointensity experiments using the Coe/Thellier method with pTRM and tail checks, and with selection criteria modified to the situation. Palaeointensities range from 50μT to 77μT. Rock magnetic experiments contribute to our understanding of the mineralogy, domain state and blocking temperature spectra.  We compare our data with predictions of the global field models ARCH3k and gufm1, and suggest that the addition of our new data will improve these models for the SW Pacific region for the most recent time period. Archaeomagnetic measurements are also used to date hangi sites by matching the palaeo-direction to an established archaeomagnetic dating model, NZPSV1k. Archaeomagnetic dating is used to resolve ambiguities in the calibration of radiocarbon dates, and shows up inconsistencies due to unreliable source material for radiocarbon dating. Archaeomagnetic dating and radiocarbon dating results are combined to give the best estimates of the best age of the hangi sites.</p>


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