scholarly journals Composition and consequences of the IntCal20 radiocarbon calibration curve

2020 ◽  
Vol 96 ◽  
pp. 22-27
Author(s):  
Paula J. Reimer
Keyword(s):  
Statistical Method ◽  
Northern Hemisphere ◽  
Calibration Curve ◽  
Working Group ◽  
Advance Rate ◽  
Prior Estimate ◽  
Over Time ◽  
Resolution Data ◽  
Radiocarbon Calibration

AbstractRadiocarbon calibration is necessary to correct for variations in atmospheric radiocarbon over time. The IntCal working group has developed an updated and extended radiocarbon calibration curve, IntCal20, for Northern Hemisphere terrestrial samples from 0 to 55,000 cal yr BP. This paper summarizes the new datasets, changes to existing datasets, and the statistical method used for constructing the new curve. Examples of the effect of the new calibration curve compared to IntCal13 for hypothetical radiocarbon ages are given. For the recent Holocene the effect is minimal, but for older radiocarbon ages the shift in calibrated ages can be up to several hundred years with the potential for multiple calibrated age ranges in periods with higher-resolution data. In addition, the IntCal20 curve is used to recalibrate the radiocarbon ages for the glaciation of the Puget Lowland and to recalculate the advance rate. The ice may have reached its maximum position a few hundred years earlier using the new calibration curve; the calculated advance rate is virtually unchanged from the prior estimate.

scholarly journals NotCal04—Comparison/Calibration 14C Records 26–50 Cal Kyr BP

Radiocarbon ◽  
2004 ◽  
Vol 46 (3) ◽  
pp. 1225-1238 ◽  
Author(s):  
J van der Plicht ◽  
J W Beck ◽  
E Bard ◽  
M G L Baillie ◽  
P G Blackwell ◽  
...  
Keyword(s):  
High Resolution ◽  
Calibration Curve ◽  
Working Group ◽  
Time Range ◽  
Data Sets ◽  
Comparison Calibration ◽  
Radiocarbon Calibration

The radiocarbon calibration curve IntCal04 extends back to 26 cal kyr B P. While several high-resolution records exist beyond this limit, these data sets exhibit discrepancies of up to several millennia. As a result, no calibration curve for the time range 26–50 cal kyr BP can be recommended as yet, but in this paper the IntCal04 working group compares the available data sets and offers a discussion of the information that they hold.

scholarly journals An Online Application for ΔR Calculation

Radiocarbon ◽  
2016 ◽  
Vol 59 (5) ◽  
pp. 1623-1627 ◽  
Author(s):  
Ron W Reimer ◽  
Paula J Reimer
Keyword(s):  
Distribution Function ◽  
Probability Distribution ◽  
Calibration Curve ◽  
Probability Distribution Function ◽  
Museum Collections ◽  
Online Program ◽  
Online Application ◽  
Radiocarbon Calibration

AbstractA regional offset (ΔR) from the marine radiocarbon calibration curve is widely used in calibration software (e.g. CALIB, OxCal) but often is not calculated correctly. While relatively straightforward for known-age samples, such as mollusks from museum collections or annually banded corals, it is more difficult to calculate ΔR and the uncertainty in ΔR for 14C dates on paired marine and terrestrial samples. Previous researchers have often utilized classical intercept methods that do not account for the full calibrated probability distribution function (pdf). Recently, Soulet (2015) provided R code for calculating reservoir ages using the pdfs, but did not address ΔR and the uncertainty in ΔR. We have developed an online application for performing these calculations for known-age, paired marine and terrestrial 14C dates and U-Th dated corals. This article briefly discusses methods that have been used for calculating ΔR and the uncertainty and describes the online program deltar, which is available free of charge.

scholarly journals DIVISION IX / COMMISSION 25 / WORKING GROUP INFRARED ASTRONOMY

2008 ◽  
Vol 4 (T27A) ◽  
pp. 313-315
Author(s):  
Eugene F. Milone ◽  
Andrew T. Young ◽  
Eva Bauwens ◽  
Roger A. Bell ◽  
Michael S. Bessell ◽  
...  
Keyword(s):  
Working Group ◽  
General Assembly ◽  
Infrared Photometry ◽  
Water Vapour Content ◽  
Atmospheric Extinction ◽  
Variable Water ◽  
Johnson System ◽  
Atmospheric Windows ◽  
New System ◽  
Over Time

As we have noted before, the WG-IR was created following a Joint Commission Meeting at the IAU General Assembly in Baltimore in 1988, a meeting that provided both diagnosis and prescription for the perceived ailments of infrared photometry at the time. The results were summarized in Milone (1989). The challenges involve how to explain the failure to systematically achieve the milli-magnitude precision expected of infrared photometry and an apparent 3% limit on system transformability. The proposed solution was to re-define the broadband Johnson system, the passbands of which had proven so unsatisfactory that over time effectively different systems proliferated although bearing the same JHKLMNQ designations; the new system needed to be better positioned and centered in the atmospheric windows of the Earth's atmosphere, and the variable water vapour content of the atmosphere needed to be measured in real time to better correct for atmospheric extinction.

Making the most of radiocarbon dating: some statistical considerations

Antiquity ◽  
1994 ◽  
Vol 68 (259) ◽  
pp. 252-263 ◽  
Author(s):  
C. E. Buck ◽  
C. D. Litton ◽  
E. M. Scott
Keyword(s):  
Calibration Curve ◽  
Radiocarbon Dating ◽  
Worked Examples ◽  
The Real ◽  
The Right ◽  
Radiocarbon Calibration

The revised radiocarbon calibration curve, published last year, extends back into the Pleistocene the radiocarbon determinations that can be converted to real calendar years. For determinations of any age, the right judgements and statistical considerations must be followed if the real information held in the determinations is to be found. Here is advice with some worked examples.

scholarly journals SHCal20 Southern Hemisphere Calibration, 0–55,000 Years cal BP

Radiocarbon ◽  
2020 ◽  
Vol 62 (4) ◽  
pp. 759-778 ◽  
Author(s):  
Alan G Hogg ◽  
Timothy J Heaton ◽  
Quan Hua ◽  
Jonathan G Palmer ◽  
Chris SM Turney ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Tree Ring ◽  
Calibration Curve ◽  
Data Sets ◽  
Errors In Variables ◽  
Time Intervals ◽  
Tree Ring Data ◽  
The Mean ◽  
Statistical Approaches

ABSTRACTEarly researchers of radiocarbon levels in Southern Hemisphere tree rings identified a variable North-South hemispheric offset, necessitating construction of a separate radiocarbon calibration curve for the South. We present here SHCal20, a revised calibration curve from 0–55,000 cal BP, based upon SHCal13 and fortified by the addition of 14 new tree-ring data sets in the 2140–0, 3520–3453, 3608–3590 and 13,140–11,375 cal BP time intervals. We detail the statistical approaches used for curve construction and present recommendations for the use of the Northern Hemisphere curve (IntCal20), the Southern Hemisphere curve (SHCal20) and suggest where application of an equal mixture of the curves might be more appropriate. Using our Bayesian spline with errors-in-variables methodology, and based upon a comparison of Southern Hemisphere tree-ring data compared with contemporaneous Northern Hemisphere data, we estimate the mean Southern Hemisphere offset to be 36 ± 27 14C yrs older.

scholarly journals Selection and Treatment of Data for Radiocarbon Calibration: An Update to the International Calibration (IntCal) Criteria

Radiocarbon ◽  
2013 ◽  
Vol 55 (4) ◽  
pp. 1923-1945 ◽  
Author(s):  
Paula J Reimer ◽  
Edouard Bard ◽  
Alex Bayliss ◽  
J Warren Beck ◽  
Paul G Blackwell ◽  
...  
Keyword(s):  
Calibration Curve ◽  
Quality Data ◽  
Calibration Data ◽  
High Quality ◽  
High Quality Data ◽  
Surface Ocean ◽  
Basic Assumptions ◽  
Calibration Curves ◽  
Curve Model ◽  
Radiocarbon Calibration

High-quality data from appropriate archives are needed for the continuing improvement of radiocarbon calibration curves. We discuss here the basic assumptions behind 14C dating that necessitate calibration and the relative strengths and weaknesses of archives from which calibration data are obtained. We also highlight the procedures, problems, and uncertainties involved in determining atmospheric and surface ocean 14C/12C in these archives, including a discussion of the various methods used to derive an independent absolute timescale and uncertainty. The types of data required for the current IntCal database and calibration curve model are tabulated with examples.

Revised ‘absolute’ dating of the early Mesolithic site of Star Carr, North Yorkshire, in the light of changes in the early Holocene tree-ring chronology

Antiquity ◽  
2000 ◽  
Vol 74 (284) ◽  
pp. 304-307 ◽  
Author(s):  
Petra Dark
Keyword(s):  
Environmental Change ◽  
Tree Ring ◽  
Calibration Curve ◽  
Early Holocene ◽  
Tree Ring Chronology ◽  
Absolute Dating ◽  
The Absolute ◽  
Holocene Environmental Change ◽  
Radiocarbon Calibration

Recent revision of the radiocarbon calibration curve for the early Holocene has implications for the ‘absolute’ date of Mesolithic sites such as Star Carr, and for their relationship to the timescale of early Holocene environmental change.

scholarly journals Revisions and Extension of the Hohenheim Oak and Pine Chronologies: New Evidence About the Timing of the Younger Dryas/Preboreal Transition

Radiocarbon ◽  
1998 ◽  
Vol 40 (3) ◽  
pp. 1107-1116 ◽  
Author(s):  
Marco Spurk ◽  
Michael Friedrich ◽  
Jutta Hofmann ◽  
Sabine Remmele ◽  
Burkhard Frenzel ◽  
...  
Keyword(s):  
Calibration Curve ◽  
Younger Dryas ◽  
Ice Cores ◽  
Early Holocene ◽  
Proxy Data ◽  
The Past ◽  
Varve Chronology ◽  
New Evidence ◽  
Radiocarbon Calibration

Oak and pine samples housed at the Institute of Botany, University of Hohenheim, are the backbone of the early Holocene part of the radiocarbon calibration curve, published in 1993 (Becker 1993; Kromer and Becker 1993; Stuiver and Becker 1993; Vogel et al. 1993). Since then the chronologies have been revised. The revisions include 1) the discovery of 41 missing years in the oak chronology and 2) a shift of 54 yr for the oldest part back into the past. The oak chronology was also extended with new samples as far back as 10,429 BP (8480 BC). In addition, the formerly tentatively dated pine chronology (Becker 1993) has been rebuilt and shifted to an earlier date. It is now positioned by 14C matching at 11,871-9900 BP (9922–7951 BC) with an uncertainty of ±20 yr (Kromer and Spurk 1998). With these new chronologies the 14C calibration curve can now be corrected, eliminating the discrepancy in the dating of the Younger Dryas/Preboreal transition between the proxy data of the GRIP and GISP ice cores (Johnsen et al. 1992; Taylor et al. 1993), the varve chronology of Lake Gościąż (Goslar et al. 1995) and the pine chronology (Becker, Kromer and Trimborn 1991).

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