Quality Dating: A Well-Defined Protocol Implemented at ETH for High-Precision 14C-Dates Tested on Late Glacial Wood

ABSTRACTAdvances in accelerator mass spectrometry have resulted in an unprecedented amount of new high-precision radiocarbon (14C) -dates, some of which will redefine the international 14C calibration curves (IntCal and SHCal). Often these datasets are unaccompanied by detailed quality insurances in place at the laboratory, questioning whether the 14C structure is real, a result of a laboratory variation or measurement-scatter. A handful of intercomparison studies attempt to elucidate laboratory offsets but may fail to identify measurement-scatter and are often financially constrained. Here we introduce a protocol, called Quality Dating, implemented at ETH-Zürich to ensure reproducible and accurate high-precision 14C-dates. The protocol highlights the importance of the continuous measurements and evaluation of blanks, standards, references and replicates. This protocol is tested on an absolutely dated German Late Glacial tree-ring chronology, part of which is intercompared with the Curt Engelhorn-Center for Archaeometry, Mannheim, Germany (CEZA). The combined dataset contains 170 highly resolved, highly precise 14C-dates that supplement three decadal dates spanning 280 cal. years in IntCal, and provides detailed 14C structure for this interval.

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Findings from an in-Depth Annual Tree-Ring Radiocarbon Intercomparison

Radiocarbon ◽

10.1017/rdc.2020.49 ◽

2020 ◽

Vol 62 (4) ◽

pp. 873-882 ◽

Cited By ~ 4

Author(s):

L Wacker ◽

E M Scott ◽

A Bayliss ◽

D Brown ◽

E Bard ◽

...

Keyword(s):

Mass Spectrometry ◽

Tree Ring ◽

High Precision ◽

Calibration Curve ◽

Accelerator Mass Spectrometry ◽

Large Datasets ◽

Accuracy And Precision ◽

Short Period ◽

Annual Resolution

ABSTRACTThe radiocarbon (14C) calibration curve so far contains annually resolved data only for a short period of time. With accelerator mass spectrometry (AMS) matching the precision of decay counting, it is now possible to efficiently produce large datasets of annual resolution for calibration purposes using small amounts of wood. The radiocarbon intercomparison on single-year tree-ring samples presented here is the first to investigate specifically possible offsets between AMS laboratories at high precision. The results show that AMS laboratories are capable of measuring samples of Holocene age with an accuracy and precision that is comparable or even goes beyond what is possible with decay counting, even though they require a thousand times less wood. It also shows that not all AMS laboratories always produce results that are consistent with their stated uncertainties. The long-term benefits of studies of this kind are more accurate radiocarbon measurements with, in the future, better quantified uncertainties.

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THE BEGINNING OF THE IRON AGE AT ARSLANTEPE: A 14C PERSPECTIVE

Radiocarbon ◽

10.1017/rdc.2021.19 ◽

2021 ◽

pp. 1-19

Author(s):

Federico Manuelli ◽

Cristiano Vignola ◽

Fabio Marzaioli ◽

Isabella Passariello ◽

Filippo Terrasi

Keyword(s):

Mass Spectrometry ◽

Bronze Age ◽

High Precision ◽

Iron Age ◽

Accelerator Mass Spectrometry ◽

Late Bronze Age ◽

13Th Century ◽

Historical Events ◽

Preliminary Results ◽

Archaeological Data

ABSTRACT The Iron Age chronology at Arslantepe is the result of the interpretation of Luwian hieroglyphic inscriptions and archaeological data coming from the site and its surrounding region. A new round of investigations of the Iron Age levels has been conducted at the site over the last 10 years. Preliminary results allowed the combination of the archaeological sequence with the historical events that extended from the collapse of the Late Bronze Age empires to the formation and development of the new Iron Age kingdoms. The integration into this picture of a new set of radiocarbon (14C) dates is aimed at establishing a more solid local chronology. High precision 14C dating by accelerator mass spectrometry (AMS) and its correlation with archaeobotanical analysis and stratigraphic data are presented here with the purpose of improving our knowledge of the site’s history and to build a reliable absolute chronology of the Iron Age. The results show that the earliest level of the sequence dates to ca. the mid-13th century BC, implying that the site started developing a new set of relationships with the Levant already before the breakdown of the Hittite empire, entailing important historical implications for the Syro-Anatolian region at the end of the 2nd millennium BC.

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Radiocarbon in 9th to 5th Century BC Tree-Ring Samples from the Ouban 1 Archaeological Site, Hiroshima, Japan

Radiocarbon ◽

10.1017/s0033822200042405 ◽

2007 ◽

Vol 49 (2) ◽

pp. 473-479 ◽

Cited By ~ 9

Author(s):

Hiromasa Ozaki ◽

Mineo Imamura ◽

Hiroyuki Matsuzaki ◽

Takumi Mitsutani

Keyword(s):

Mass Spectrometry ◽

Tree Ring ◽

Calibration Curve ◽

Accelerator Mass Spectrometry ◽

Wood Sample ◽

Archaeological Site ◽

Short Term ◽

Statistical Errors ◽

Term Fluctuation

In order to investigate the regional atmospheric radiocarbon offset, accelerator mass spectrometry (AMS) 14C measurements were made on 5-yr increments of a Japanese wood sample dendrochronologically dated to 820–436 BC. The 14C data from the Japanese tree-ring samples were compared with the IntCal04 calibration curve (Reimer et al. 2004). In most parts, the differences between IntCal04 and 14C dates in the Japanese tree-ring samples were within experimental statistical errors. At around 680 BC, however, significant differences of up to 100 14C yr were observed. These differences may indicate either regional offsets in Japan or the short-term fluctuation of a subdecadal timescale in atmospheric 14C variations.

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REASSESSMENT OF UNCERTAINTY EXPANSION BY LINEAR ADDITION OF LONG-TERM COMPONENTS FROM TOP-DOWN INFORMATION

Radiocarbon ◽

10.1017/rdc.2021.96 ◽

2021 ◽

pp. 1-15

Author(s):

G Salazar ◽

S Szidat

Keyword(s):

Mass Spectrometry ◽

Measurement Uncertainty ◽

High Precision ◽

Accelerator Mass Spectrometry ◽

Expanded Uncertainty ◽

Top Down ◽

Bottom Up ◽

Linear Addition

ABSTRACT Since radiocarbon accelerator mass spectrometry (14C AMS) is considered a high-precision technique, reassessment of the measurement uncertainty has been a topic of interest. Scientists from analytical and metrological fields have developed the top-down and bottom-up measurement of uncertainty approaches. The 14C quoted error should approximate the uncertainty of long-term repetitions of the top-down approach in order to be realistic. The novelty of this paper is that the uncertainty of both approaches were approximated to each other. Furthermore, we apportioned the graphitization, instrumentation, and bias components in order to additively expand the quoted error. Our results are comparable to error multipliers and to long-term repeatability studies reported by other laboratories. Our laboratory was established in late 2012 with N2 as stripper gas and 7 years later, we changed to helium stripper. Thus, we were able to compare both gases, and demonstrate that helium is a better stripper gas. In absolute F14C units, the ranges of graphitization+bias combined uncertainties were (0.7 to 4.1) × 10–3 for N2 and (0.7–3.0) × 10–3 for He depending on the standard 14C content. The error multiplier for He defined as the expanded uncertainty over quoted error, in average, was 1.7; while without the bias, the multiplier was 1.3.

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Bayesian Analysis of High-Precision AMS14C Dates from a Prehistoric Mexican Shellmound

Radiocarbon ◽

10.1017/s0033822200056526 ◽

2011 ◽

Vol 53 (2) ◽

pp. 245-259 ◽

Cited By ~ 29

Author(s):

Douglas J Kennett ◽

Brendan J Culleton ◽

Barbara Voorhies ◽

John R Southon

Keyword(s):

Mass Spectrometry ◽

Bayesian Analysis ◽

High Precision ◽

Accelerator Mass Spectrometry ◽

Archaic Period ◽

Analytical Error ◽

Statistical Framework ◽

Radiocarbon Chronology

We establish a precision accelerator mass spectrometry (AMS) radiocarbon chronology for the Archaic period Tlacuachero shellmound (Chiapas, Mexico) within a Bayesian statistical framework. Carbonized twig samples were sequentially selected from well-defined stratigraphic contexts based on iterative improvements to a probabilistic chronological model. Analytical error for these measurements is ±15 to 2014C yr. This greater precision and the absence of stratigraphic reversals eclipses previous14C work at the site. Based on this, we establish a chronological framework for a sequence of 3 clay floors dating to between 4930 and 4270 cal BP and determine that the bedded shell deposits that formed the mound accumulated rapidly during 2 episodes: a lower 2-m section below the floors that accumulated over a 0–150 cal yr period at 5050–4875 cal BP and, an upper 3.5-m section above the floors that accumulated over a 0–80 cal yr period at 4380–4230 cal BP.

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Radiocarbon Calibration for Japanese Wood Samples

Radiocarbon ◽

10.1017/s0033822200032410 ◽

2003 ◽

Vol 45 (1) ◽

pp. 81-89 ◽

Cited By ~ 23

Author(s):

Minoru Sakamoto ◽

Mineo Imamura ◽

Johannes Van der Plicht ◽

Takumi Mitsutani ◽

Makoto Sahara

Keyword(s):

Mass Spectrometry ◽

North America ◽

Tree Ring ◽

Calibration Curve ◽

Accelerator Mass Spectrometry ◽

The Difference ◽

Radiocarbon Calibration

The radiocarbon content of Japanese cedars was measured by accelerator mass spectrometry for decadal tree-ring samples from the period of 240 BC to AD 900. Conventional gas counting was also used for part of the samples. The data were compared with the INTCAL98 calibration curve (Stuiver et al. 1998). The results indicate that the difference in atmospheric 14C between Japan and North America or Europe is negligible at this period, less than 18 14C yr using an average of 50 yr. However, in the period of about AD 100 to about AD 200, we cannot exclude the possibility of a deviation of the order of 30 to 40 14C yr to the older ages.

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Tree-Ring Dating and AMS Wiggle-Matching of Wooden Statues at Neunggasa Temple in South Korea

Radiocarbon ◽

10.1017/s0033822200046026 ◽

2010 ◽

Vol 52 (3) ◽

pp. 924-932 ◽

Cited By ~ 3

Author(s):

Won-Kyu Park ◽

Yojung Kim ◽

Ah-Reum Jeong ◽

Sang-Kyu Kim ◽

Jung-Ae Oh ◽

...

Keyword(s):

Mass Spectrometry ◽

Confidence Interval ◽

South Korea ◽

Tree Ring ◽

Tree Rings ◽

Accelerator Mass Spectrometry ◽

Early Spring ◽

Radiocarbon Date ◽

Historical Document ◽

Natural Drying

This paper reports the results of tree-ring dating and accelerator mass spectrometry (AMS) wiggle-matching for wooden Buddhist statues stored at the Eungjindang Hall of Neunggasa Temple, South Korea. Among 23 statues, 10 were successfully dated by tree rings. The cutting date of logs used for the statues was determined as some time between late fall 1684 and early spring 1685 when the bark ring (AD 1684) completed latewood formation. The 95.4% confidence interval of a radiocarbon date (cal AD 1688–1713, 2 σ), which was obtained by wiggle-matching 7 samples of a statue, is similar to the dendro-date (AD 1684). A historical document recorded that the statues in the Eungjindang of Neunggasa were dedicated in July 1685. The dendro-date and written record indicate that Eungjindang statues were made within 3–8 months after log cutting. This seems rather short if we consider the period required for natural drying to avoid defects such as cracking and crooking.

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Dating Polar Ice by 14C Accelerator Mass Spectrometry

Radiocarbon ◽

10.1017/s0033822200007530 ◽

1986 ◽

Vol 28 (2A) ◽

pp. 417-423 ◽

Cited By ~ 25

Author(s):

Michael Andree ◽

Juerg Beer ◽

H P Loetscher ◽

Ernst Moor ◽

Hans Oeschger ◽

...

Keyword(s):

Mass Spectrometry ◽

Model Calculation ◽

Tree Ring ◽

Seasonal Variations ◽

Accelerator Mass Spectrometry ◽

Ice Core ◽

Air Bubbles ◽

Polar Ice ◽

Rheologic Model

Results of 14C/12C ratio measurements on CO2 extracted from air bubbles in polar ice are presented. The samples investigated originate from the Dye 3, South Greenland, deep ice core and span approximately the last 10,000 years. The results are calibrated with tree-ring records. The 14C ages are compared with information obtained from seasonal variations of ice-core parameters and rheologic model calculation.

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Towards a Radiocarbon Chronology of the Late-Glacial: Sample Selection Strategies

Radiocarbon ◽

10.1017/s0033822200041679 ◽

2001 ◽

Vol 43 (2B) ◽

pp. 1007-1019 ◽

Cited By ~ 43

Author(s):

M J C Walker ◽

C Bryant ◽

G R Coope ◽

D D Harkness ◽

J J Lowe ◽

...

Keyword(s):

Mass Spectrometry ◽

Accelerator Mass Spectrometry ◽

Sample Selection ◽

Late Glacial ◽

Plant Macrofossils ◽

Sampling Strategies ◽

Radiocarbon Dates ◽

Selection Strategies ◽

Beta Counting ◽

Radiocarbon Chronology

This paper outlines a dating program designed to test the reproducibility of radiocarbon dates on different materials of Late-Glacial age (plant macrofossils, fossil beetle remains, and the “humic” and “humin” chemical fractions of limnic sediments) using a combination of radiometric (beta counting) and accelerator mass spectrometry (AMS) techniques. The results have implications for the design of sampling strategies and for the development of improved dating protocols, both of which are important if a high-precision 14C chronology for the Late-Glacial is to be achieved.

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