An illustrated guide to measuring radiocarbon from archaeological samples (original) (raw)
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Developments in radiocarbon calibration for archaeology
2006
This update on radiocarbon calibration results from the 19th International Radiocarbon Conference at Oxford in April 2006, and is essential reading for all archaeologists. The way radiocarbon dates and absolute dates relate to each other differs in three periods: back to 12 400 cal BP, radiocarbon dates can be calibrated with tree rings, and the calibration curve in this form should soon extend back to 18 000 cal BP. Between 12 400 and 26 000 cal BP, the calibration curves are based on marine records, and thus are only a best estimate of atmospheric concentrations. Beyond 26 000 cal BP, dates have to be based on comparison (rather than calibration) with a variety of records. Radical variations are thus possible in this period, a highly significant caveat for the dating of middle and lower Paleolithic art, artefacts and animal and human remains.
Radiocarbon Dating in Archaeology: Interdisciplinary aspects and consequences (An overview)
AIP Conference Proceedings 1852, 060006 (2017); doi: 10.1063/1.4984870 (Theme issue: L. Trache and D. G. Ghiță (eds), Exotic Nuclei and Nuclear/Particle Astrophysics (VI). Physics with Small Accelerators. Proceedings of the Carpathian Summer School of Physics 2016 (CSSP16)) , 2017
OPEN ACCESS of full text at: http://aip.scitation.org/toc/apc/1852/1\. Abstract. This paper is an overview of recent developments in the radiocarbon dating of the most frequently analyzed archaeological materials – wood, short-lived plants, and human and animal bones – and draws attention to two sets of consequences. Firstly, while radiocarbon dating has become more accessible to archaeologists thanks to an increase in the number of laboratories, a lowering of prices, and a reduction in sample sizes, it has also grown far more dependent on fields of research, other than the traditional chemical pretreatment of samples and the physics involved in their measurement, such as wood anatomy and other fields of botany, stable isotope-based diet studies, geochemistry, micromorphology, statistics, etc., most of which are not easily accessible by the vast majority of users of radiocarbon dating (and sometimes not familiar to practicing archaeologists). Secondly, given that, on the one hand, there is still much scope for research in radiocarbon dating and, on the other, archaeological sites are a limited resource, there is need to create archives containing the detailed documentation of samples and, whenever possible, sample residues.
Radiocarbon Dating in Archaeology: Triangulation and Traceability
Data Journeys in the Sciences, 2020
When radiocarbon dating techniques were applied to archaeological material in the 1950s they were hailed as a revolution. At last archaeologists could construct absolute chronologies anchored in temporal data backed by immutable laws of physics. This would make it possible to mobilize archaeological data across regions and time-periods on a global scale, rendering obsolete the local and relative chronologies on which archaeologists had long relied. As profound as the impact of 14C dating has been, it has had a long and tortuous history now described as proceeding through three revolutions, each of which addresses distinct challenges of capturing, processing and packaging radiogenic data for use in resolving chronological puzzles with which archaeologists has long wrestled. In practice, mobilizing radiogenic data for archaeological use is a hard-won achievement; it involves multiple transformations that, at each step of the way, depend upon a diverse array of technical expertise and ...
Radiocarbon, 2019
Since 1993 Historic England (and its predecessor English Heritage) has commissioned 9074 radiocarbon (14C) measurements on archaeological samples. Over 80% of these have been interpreted within formal Bayesian statistical models. The multiple strands of reinforcing evidence incorporated in these models provide precise chronologies that make stringent demands on the accuracy of the 14C results included in the analysis. Inter-laboratory replication is consequently a routine part of model construction and validation. We report an analysis of replicate measurements on 1089 archaeological samples. It is clear that laboratory reproducibility accounts for only part of the observed variation. The type of material dated is also critical to the reproducibility of measurements, with some sample types proving particularly problematic.
Memoirs of the Society for American Archaeology, 1951
The Preceding discussions have considered the radiocarbon dates in relation to a number of archaeological, geological, and palynological problems. It remains to consider the endeavor as a whole, and to reach some conclusions concerning its present and future value and usefulness. Of primary importance is a consideration of what the dates mean. Basic to this is an understanding of the statistics involved. At the request of the Committee, Arnold, who has been intimately associated with the project, has kindly contributed the following explanatory paragraphs:It seems worth while to review briefly the physical…
Radiocarbon, 2013
For the older part of the radiocarbon dating range, the IntCal13 curve provides the “state of the art” for terrestrial calibration based on all available data. It is constructed from different records, each of which by themselves could be used as a “comparison tool,” depending on the research objectives. This paper discusses the pros and cons of different approaches that can be taken when using 14C dates from this time range where the agreement amongst the underlying data sets is poorer than in other time periods. The discussion is illustrated with example calibrations against IntCa09, IntCal13, and comparisons to the Suigetsu record. The examples and discussion arc aimed at users of terrestrial 14C dates, in particular Upper Paleolithic archaeologists and those working with environmental terrestrial materials in the same time range.
Radiocarbon and the Old World Archaeology: Shaping a Chronological Framework
Radiocarbon, 2009
The inception of the radiocarbon dating method in 1949 was immediately supported by many archaeologists. In the following 2 decades, many important archaeological sites in the Old World were dated, marking the beginning of building a reliable chronological framework for prehistoric and early historic cultural complexes worldwide. The author presents an observation of some of the most important results in establishing a chronology for Old World archaeology, based on14C dating performed in the last 50 yr. An extensive bibliography should help scholars to get acquainted with early summaries on archaeological chronologies based on14C data and their evaluation, as well as with some recent examples of the application of14C dating in Old World archaeology.
British Museum Natural Radiocarbon Measurements VI
Radiocarbon, 1969
Dates listed below are based on measurements made up to May 1968, and cover a period during which the technique of gas proportional counting using CO2 was gradually replaced by liquid scintillation counting using benzene. The gas counting measurements were carried out by the method and techniques previously described (Barker and Mackey, 1968) the only modifications being the replacement of some old electronic units by more stable solid-state equipment; proportional counting results are indicated in the text by (P) at the end of the relevant sample descriptions. Liquid scintillation counting, which is now the preferred method in this laboratory, is carried out using a Packard Tri-Carb liquid scintillation spectrometer model 3315/AES fitted with selected low-noise quartz-faced photomultipliers. Normally 3 ml of benzene is prepared from each sample. This is dissolved in 12 ml of scintillation grade toluene containing 5 gm/liter of scintillator (PPO) and the solution is measured in a standard low-potassium glass vial at a temperature of 0°C. Photomultiplier E.H.T., amplifier, and channel width settings are optimized for C14, and measurements are carried out at ca. 65% efficiency of detection for C14 to eliminate interference from any tritium which may be present in the benzene. Under these circumstances the background is approx. 8.6 cpm and the modern (95% A0X) is approx. 24.0 cpm. Samples are counted in groups of 3 to 5 together with background and modern reference samples and are measured for at least one week, the instrument being set to cycle at 100 min intervals. In this period, the counts accumulated are such that the background is always measured to a statistical accuracy of better than 1% and most other samples to a higher accuracy than this. Background and modern counts used in the calculation of each result are only those relevant to the period of measurement of that particular sample. Statistical analysis of groups of replicate measurements made under these conditions over a very long period of time has demonstrated the excellent long-term stability of the equipment and indicates that the technique is quite capable of achieving results of very high statistical accuracy when required. SAMPLE DESCRIPTIONS ARCHAEOLOGIC SAMPLES A. Crete Knossos series Five samples from Neolithic settlement of Knossos, Crete (35° 31' N Lat, 25 ° 20' E Long), from sounding below central court of Minoan Palace (Evans, 1964a,b). Coll. 1960 and subm. by J. D. Evans, Inst. of Archaeol., Univ. of London, for comparison with unexpectedly early dates previously obtained for Knossos Neolithic, BM-124, 8050 ± 180 and BM-126, 7000 + 180 (Radiocarbon, 1963, v. 5, p. 104). 7570 ± 150 BM-272. Knossos 2 5620 B.C. Sample 2, ref. Area AC, Level 24. Charcoal from Occupation layer assoc. with 1st brick houses and immediately overlying earliest camp occupation above bedrock (Stratum IX, Evans, 1964b). Expected age early 6th millennium B.C. based on BM-124 and BM-126. (P) 6210 ± 150 BM-273. Knossos 3 4260 B.C. Sample 3, ref. Area AC, Level 17. Charcoal from habitation deposit in Stratum VI (Evans, 1964b). Expected age late 6th millennium B.C. based on BM-124 and BM-126. (P) 6140 ± 150 BM-274. Knossos 4 4190 B.C. Sample 4, ref. Area A, Level 15. Charcoal from habitation level in Stratum V (Evans, 1964b). Expected age end of 6th millennium B.C. based on BM-124 and BM-126. (P)
Important features of the new radiocarbon calibration curves
Quaternary Science Reviews, 2006
Calibration from the radiocarbon to the calendar scale is essential for developing chronologies in palaeoenvironmental or archaeological studies. We report here on the new internationally agreed radiocarbon calibration curves, which replace the 1998 curves. We discuss some of the important features of the curves and illustrate how modern Bayesian statistical methods and groups of related radiocarbon determinations can considerably improve chronological resolution. r