Four Coptic Textiles from the Louvre Collection 14C Redated after 55 Years

Radiocarbon ◽  
2014 ◽  
Vol 56 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Mark van Strydonck ◽  
Dominique Bénazeth
Keyword(s):  
Standard Deviation ◽  
Radiocarbon Dating ◽  
Large Standard Deviation ◽  
Art Historians ◽  
Dating Method

Dating of Coptic textiles performed in the early days of the radiocarbon dating method was revisited. In 1957–1958, Louvre curator and art historian P du Bourguet had 4 Coptic textiles 14C dated by the Saclay laboratory. The results were rejected, not because of the large standard deviation (>100 yr), but because their ages did not support his chronological framework based on typological comparison. Furthermore, textiles with comparable ages were dated several centuries apart. As a result of this investigation, for many decades art historians rejected 14C as a dating tool for Coptic textiles. Re-examination of the old data and new 14C analyses revealed that mistakes were made, both in the reporting as in the interpretation of the data and that the textiles are much older than presumed.

Observations of Precipitation Size and Fall Speed Characteristics within Coexisting Rain and Wet Snow

2006 ◽  
Vol 45 (10) ◽  
pp. 1450-1464 ◽  
Author(s):  
Sandra E. Yuter ◽  
David E. Kingsmill ◽  
Louisa B. Nance ◽  
Martin Löffler-Mang
Keyword(s):  
Particle Size ◽  
Standard Deviation ◽  
Volume Fraction ◽  
Bimodal Distribution ◽  
Particle Sizes ◽  
Large Standard Deviation ◽  
Air Temperatures ◽  
Isothermal Layer ◽  
Wet Snow ◽  
Fall Speed

Abstract Ground-based measurements of particle size and fall speed distributions using a Particle Size and Velocity (PARSIVEL) disdrometer are compared among samples obtained in mixed precipitation (rain and wet snow) and rain in the Oregon Cascade Mountains and in dry snow in the Rocky Mountains of Colorado. Coexisting rain and snow particles are distinguished using a classification method based on their size and fall speed properties. The bimodal distribution of the particles’ joint fall speed–size characteristics at air temperatures from 0.5° to 0°C suggests that wet-snow particles quickly make a transition to rain once melting has progressed sufficiently. As air temperatures increase to 1.5°C, the reduction in the number of very large aggregates with a diameter > 10 mm coincides with the appearance of rain particles larger than 6 mm. In this setting, very large raindrops appear to be the result of aggregrates melting with minimal breakup rather than formation by coalescence. In contrast to dry snow and rain, the fall speed for wet snow has a much weaker correlation between increasing size and increasing fall speed. Wet snow has a larger standard deviation of fall speed (120%–230% relative to dry snow) for a given particle size. The average fall speed for observed wet-snow particles with a diameter ≥ 2.4 mm is 2 m s−1 with a standard deviation of 0.8 m s−1. The large standard deviation is likely related to the coexistence of particles of similar physical size with different percentages of melting. These results suggest that different particle sizes are not required for aggregation since wet-snow particles of the same size can have different fall speeds. Given the large standard deviation of fall speeds in wet snow, the collision efficiency for wet snow is likely larger than that of dry snow. For particle sizes between 1 and 10 mm in diameter within mixed precipitation, rain constituted 1% of the particles by volume within the isothermal layer at 0°C and 4% of the particles by volume for the region just below the isothermal layer where air temperatures rise from 0° to 0.5°C. As air temperatures increased above 0.5°C, the relative proportions of rain versus snow particles shift dramatically and raindrops become dominant. The value of 0.5°C for the sharp transition in volume fraction from snow to rain is slightly lower than the range from 1.1° to 1.7°C often used in hydrological models.

scholarly journals Radiocarbon Dating the Last Glacial-Interglacial Transition (Ca. 14–9 14C Ka Bp) in Terrestrial and Marine Records: The Need for New Quality Assurance Protocols

Radiocarbon ◽  
2000 ◽  
Vol 42 (1) ◽  
pp. 53-68 ◽  
Author(s):  
J John Lowe ◽  
Michael J C Walker
Keyword(s):  
Quality Assurance ◽  
Radiocarbon Dating ◽  
Ice Core ◽  
Time Interval ◽  
Last Glacial ◽  
Cold Stage ◽  
Dating Method ◽  
New Challenges ◽  
Important Time ◽  
The Last Glacial

The publication during the 1990s of Greenland ice-core records spanning the transition from the Last Cold Stage to the present interglacial (ca. 14–9 14C ka BP) presented new challenges to scientists working on marine and terrestrial sequences from this important time interval. In particular, there is now an overriding imperative to increase the levels of precision by which events during this period can be dated and correlated. We review some of the problems commonly encountered when using radiocarbon dating for these purposes, and consider some of the new approaches that will be required if this dating method is to provide a basis for a high precision chronology for the last glacial-interglacial transition.

Delayed Hardening and Reactivation of Binder Calcite, Common Problems in Radiocarbon Dating of Lime Mortars

Radiocarbon ◽  
2020 ◽  
Vol 62 (3) ◽  
pp. 565-577 ◽  
Author(s):  
Alf Lindroos ◽  
Åsa Ringbom ◽  
Jan Heinemeier ◽  
Irka Hajdas ◽  
Jesper Olsen
Keyword(s):  
Carbon Dioxide ◽  
Phosphoric Acid ◽  
Calcium Hydroxide ◽  
Radiocarbon Dating ◽  
Lime Mortars ◽  
Dating Method ◽  
Common Problems

ABSTRACTWhen sampling mortars for radiocarbon (14C) dating it is crucial to ensure that the sample has hardened rapidly relative the resolution of the dating method. Soft and porous lime mortars usually fulfill this criterion if the samples are taken from an uncovered surface from less than a few centimeters deep. However, hard, concrete-like mortars may be impermeable for carbon dioxide and even the outermost centimeters may still contain uncarbonated calcium hydroxide. These mortars may harden very slowly and contain carbonate that formed centuries or even millennia after the original building phase, and they can still be alkaline and capture modern 14C, causing younger 14C ages than the actual construction age. Another problem is reactivation of the binder carbonate if it has been partly decarbonated during a fire later on in its history. It will be shown that these young carbonates dissolve rapidly in phosphoric acid and in many cases a reasonable 14C age can be read from 14C profiles in sequential dissolution if the measurements from initially formed carbon dioxide are disregarded. However, if a mortar was made waterproof deliberately by adding crushed or ground tile, as in Roman cocciopesto mortars, it may be very difficult to get a conclusive dating.

Radiocarbon Dating and Egyptian Chronology—From the “Curve of Knowns” to Bayesian Modeling

2016 ◽  
Author(s):  
Felix Höflmayer
Keyword(s):  
Bayesian Modeling ◽  
Radiocarbon Dating ◽  
State Of The Art ◽  
Near Eastern ◽  
Open Questions ◽  
The World ◽  
Dating Method ◽  
To Come ◽  
Almost All ◽  
Egyptian Archaeology

Radiocarbon dating has become a standard dating method in archaeology almost all over the world. However, in the field of Egyptology and Near Eastern archaeology, the method is still not fully appreciated. Recent years have seen several major radiocarbon projects addressing Egyptian archaeology and chronology that have led to an intensified discussion regarding the application of radiocarbon dating within the field of Egyptology. This chapter reviews the contribution of radiocarbon dating to the discipline of Egyptology, discusses state-of-the-art applications and their impact on archaeological as well as chronological questions, and presents open questions that will be addressed in the years to come.

14C Dating of Historical Buildings in Japan

Radiocarbon ◽  
2014 ◽  
Vol 56 (02) ◽  
pp. 691-697 ◽  
Author(s):  
Nanae Nakao ◽  
Minoru Sakamoto ◽  
Mineo Imamura
Keyword(s):  
Research Method ◽  
Radiocarbon Dating ◽  
Historical Buildings ◽  
14C Dating ◽  
History Of ◽  
Dating Method ◽  
Japanese Architecture

The radiocarbon dating method was applied to the study of Japanese traditional wooden buildings. The traditional Japanese architecture studied includes the Main Hall of Banna-ji Temple (Buddhist building), Sekisui-in of Kozan-ji Temple (noble house), Hakogi-ke house (farmhouse), and Kawai-ke house (townhouse).14C dating proved useful as a research method to better understand the history of these buildings and Japanese architecture as a whole.

Age determination in dogs using ocular light reflection, dental abrasion and tartar

2015 ◽  
Vol 43 (05) ◽  
pp. 317-322
Author(s):  
K. Failing ◽  
R. Neiger ◽  
K. Gesierich
Keyword(s):  
Logistic Regression ◽  
Standard Deviation ◽  
Age Estimation ◽  
Regression Models ◽  
Age Determination ◽  
Light Reflection ◽  
Animal Shelters ◽  
Large Standard Deviation ◽  
Logistic Regression Models ◽  
Final Equation

SummaryObjective: The knowledge of an animal’s age is important for disease probability, prognoses, or epidemiological questions, but unfortunately, it is often unknown for dogs in animal shelters. A simple estimating procedure is preferable being quick and easy to perform, even for nonveterinarians. Material and methods: In 295 dogs the dimension of light reflection (diameter in millimetres), visible on the posterior lens capsule using a penlight, the grade of dental abrasion and dental tartar were documented photographically and the exact weight and age in days were obtained. These photographs were evaluated blinded. The dogs were divided randomly into two groups. The first group was used to establish a model for age determination using linear and logistic regression models considering the documented parameters, which was then validated with the data of the second group. Results: The size of ocular light reflection and age correlated significantly (r = 0.781; p < 0.001; sy,x = 2.45 years [SD of y for given x]). The linear regression model gave the final equation: Estimated age [months] = 13.954 + 33.400 × lens reflection [mm] + 8.406 × dental abrasion [grade] + 8.871 × tartar [grade] with a standard error of estimation of 2.26 years. Conclusion and clinical relevance: Age determination, even based on three parameters results in a large standard deviation making age estimation in dogs very crude.

scholarly journals 14C Dating Compared to Art Historical Dating of Roman and Coptic Textiles from Egypt

Radiocarbon ◽  
2004 ◽  
Vol 46 (1) ◽  
pp. 231-244 ◽  
Author(s):  
Mark Van Strydonck ◽  
Antoine De Moor ◽  
Dominique Bénazeth
Keyword(s):  
Radiocarbon Dating ◽  
Interquartile Range ◽  
14C Dating ◽  
Art Historians ◽  
Representative Selection ◽  
The Individual ◽  
Selection Of ◽  
Individual Objects

A representative selection of Roman and Coptic textiles is used to compare the radiocarbon dating results with the chronology proposed by art historians. In some cases, the comparison was made on individual objects, but in other cases, groups of stylistically and/or technologically related textiles were compared. In the case of the latter, the interquartile range was calculated. The results of this comparison show that some individual samples and groups are dated older than expected, while for another group the opposite is the case. One group was matching well with the presumed period as a whole, but not on the basis of the individual pieces. The analyses showed the necessity of 14C dating to obtain a more accurate dating of Coptic textiles.

Predictable Low Enrichment of Methane Isotopes by Clusius-Dickel Thermal-Diffusion Columns for Use in Radiocarbon Dating Technique

1971 ◽  
Vol 26 (8) ◽  
pp. 1365-1370 ◽  
Author(s):  
H. Erlenkeuser
Keyword(s):  
Thermal Diffusion ◽  
Radiocarbon Dating ◽  
Total Sample ◽  
High Reproducibility ◽  
Operation Conditions ◽  
Sample Enrichment ◽  
Diffusion Column ◽  
Sample Amount ◽  
Dating Method ◽  
Optimal Values

By means of the Clusius-Dickel thermal-diffusion column the range of the radiocarbon dating method may be extended by 20 000 years. It is shown in this work that the total sample amount required is reasonably low, if column dimensions are suitably chosen. The enrichment run time and the length of the thermal-diffusion column will allow sample enrichment in routine operation. Optimal values of column dimensions and operation conditions are calculated.With an all metal thermal-diffusion column that has been carefully constructed, a high reproducibility is found. The stationary as well as the non-stationary state operation are in agreement with column theory within 1%, concerning the enrichment both of C13H4 and C14H4 in methane. The theory has been evaluated by numerical methods

scholarly journals Development of Radiocarbon Dating Method for Degraded Bone Samples from Korean Archaeological Sites

Radiocarbon ◽  
2011 ◽  
Vol 53 (1) ◽  
pp. 129-135 ◽  
Author(s):  
K J Kim ◽  
W Hong ◽  
J H Park ◽  
H J Woo ◽  
G Hodgins ◽  
...  
Keyword(s):  
Carbon Content ◽  
Depth Profile ◽  
Radiocarbon Dating ◽  
Archaeological Site ◽  
Archaeological Sites ◽  
The Past ◽  
Dating Method ◽  
Study Support ◽  
Ultrafiltration Process

The development of radiocarbon dating for degraded bone samples collected at Korean archaeological sites has been successful through the characterization of raw bone C/N ratios and application of an ultrafiltration method. It was found that the C/N ratios of raw bone samples are inversely proportional to the carbon content and residue amount after gelatinization. We have examined a few dozen Korean archaeological bone samples for this study. Well-preserved bone samples are found to be physically dense. The range of C/N ratios of Korean raw bone samples ranged from 3.4 to 74. We found that the C/N ratios of degraded raw bone samples can be used to determine whether 14C samples are acceptable for normal pretreatment processing and eventual dating. The results of this study support that even if the C/N ratio of a degraded raw bone sample is 11, extraction of collagen for bone dating is feasible by a carefully designed ultrafiltration process. Our preliminary 14C dating results of a depth profile of Gunang-gul Cave, an archaeological site in Danyang, Korea, indicate that this site has been either geologically or anthropologically disturbed in the past, with 14C ages ranging from 28,910 ± 200 to 48,090 ± 1050 yr BP. The C/N ratios of the collagen samples of Gunang-gul were determined to be 3.2–3.6. Our study establishes a new guide for the pretreatment of degraded bone samples such as those collected in Korea for 14C dating.

scholarly journals A 23-Year Retrospective Blind Check of Accuracy of the Copenhagen Radiocarbon Dating System

Radiocarbon ◽  
1999 ◽  
Vol 41 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Kaare L Rasmussen ◽  
Henrik Tauber ◽  
Niels Bonde ◽  
Kjeld Christensen ◽  
Páll Theodórsson
Keyword(s):  
Standard Deviation ◽  
Tree Rings ◽  
Radiocarbon Dating ◽  
Average Difference ◽  
Blind Test ◽  
Term Stability ◽  
Long Term Stability ◽  
Measuring Accuracy ◽  
Sample Age

A 23-yr record of the measuring accuracy of the Copenhagen radiocarbon dating laboratory has retrospectively been provided through a true blind test. A total of 92 samples of oak from old tree trunks were dated in the period 1971 to 1993 and their dendrochronological age determined independently. The 14C activity of the dendrochronological samples measured in the Copenhagen radiocarbon laboratory was compared to the activity of the tree rings of the same age measured by Stuiver and Pearson (1993) for calibration purposes. The average difference was found to be 54 ± 72 14C yr. The results further indicate that the actual standard deviation is only 7% higher than that quoted by the laboratory. The investigation has shown a long-term stability of laboratory accuracy with no systematic laboratory variations either with respect to sample age or to the time of measurement from 1971 to 1993.

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