Dendrochronology – The MAD Carbon-14 Consensus

Dendrochronology - The MAD Carbon-14 Consensus

In 1982 Dendrochronology and Radiocarbon Dating reached a Carbon-14 calibration consensus based upon a Bristlecone Pine chronology.

Calibration of radiocarbon dates

Introduction
It is now quite generally accepted that “conventional” radiocarbon dates need to be “calibrated” because of temporal variations in the radiocarbon content of atmospheric carbon dioxide.

The discovery of this phenomenon was made largely by the pioneering work of de Vries (1958; 1959) and Willis, Tauber, and Munnich (1960), and subsequently has been carried on by more than a dozen radiocarbon laboratories worldwide (for a review see Damon, Lerman, and Long, 1978).

The assessment of these variations relies on the measurement of “C activity in samples of known age.

Dendrochronologically dated wood has proved to be an ideal material for such measurements, and currently all radiocarbon calibrations are based on measurements of 14C activity in wood.

The longest chronology extant is that of the bristlecone pine, resulting from the efforts of Schulman (1956) and Ferguson (1969; 1970; 1972).

It reaches continuously to 8681 years ago, and to 8580 years ago with sufficient material to allow radiocarbon dating. This work includes measurements on wood as old as 8000 years.

Calibration of radiocarbon dates – J. Klein et al. – Radiocarbon, 24, 1982
https://journals.uair.arizona.edu/index.php/radiocarbon/article/download/748/753?origin=publication_detail

The consensus was very important for both parties.

Radiocarbon Dating wanted to “understand more fully the nature and causes of the variability of radiocarbon dates” whilst Dendrochronology needed to ensure their Bristlecone Pine chronology [aka narrative] based upon a “new dendrochronological species, in a new area, and (increasingly) in a new time period” was not derailed by Radiocarbon Dating.

As one of the principal objectives of this analysis has been to understand more fully the nature and causes of the variability of radiocarbon dates, the data were examined carefully for signs of non-random errors.

Calibration of radiocarbon dates – J. Klein et al. – Radiocarbon, 24, 1982
https://journals.uair.arizona.edu/index.php/radiocarbon/article/download/748/753?origin=publication_detail

This study brought out what was very early realized: that in working with a new dendrochronological species, in a new area, and (increasingly) in a new time period, we would be much more secure in chronology building to work with material of a proven, but safe quality.

Much of the data collected in the early stage of investigation was of an extremely difficult quality, with a very low average ring width (many specimens had more than 100 rings per radial inch), a high mean sensitivity, and many locally absent and missing rings.

A 7104 Year Annual Tree Ring Chronology for Bristlecone Pine, Pinus Aristata, from the White Mountains, California – C. W. Ferguson – Tree-Ring Bulletin, Volume 29 (1969)
https://arizona.openrepository.com/arizona/bitstream/10150/259957/1/trb-29-03-04-003-029.pdf

Bristlecone Pine Wood

The discussions between the two disciplines must have had a few interesting moments because Radiocarbon Dating [much to their surprise] conceded that “there is significant evidence of systematic differences between the laboratories”.

Much to our surprise and despite previous findings to the contrary (Damon, Lerman, and Long, 1978; Clark, 1975; Damon, 1970), there is significant evidence of systematic differences between the laboratories represented.

Systematic Differences

Calibration of radiocarbon dates – J. Klein et al. – Radiocarbon, 24, 1982
https://journals.uair.arizona.edu/index.php/radiocarbon/article/download/748/753?origin=publication_detail

Little else is revealed regarding the discussions that led to the calibration consensus based upon a composite “workshop data set”.

1982 - J Klein et al - Calibration of radiocarbon dates
The composite “workshop data set” is plotted against the 6th order polynominal regressed on the logarithmically scaled data.

Calendric age minus conventional radiocarbon age is the ordinate; the calendric age is the abscissa.

Positive values represent radiocarbon ages that are too young (too recent) and, consequently, atmospheric concentrations were greater than that of the standard atmosphere of 1890…

Calibration of radiocarbon dates – J. Klein et al. – Radiocarbon, 24, 1982
https://journals.uair.arizona.edu/index.php/radiocarbon/article/download/748/753?origin=publication_detail

However, an analysis of the “workshop data set” reveals that Radiocarbon Dating of the Bristlecone Pine chronology is far from a perfect fit and that the rounded consensus calibration curve is derived from a very jagged, saw tooth dataset.

Perfect Fit

Furthermore, the beginning of the chronology [in modern times] represents a major theoretical problem for Radiocarbon Dating because the living outer layers of the Bristlecone Pines appear to be hugely deficient in Carbon-14 [i.e. carbon-14 dating indicates these outer layers are a lot older than suggested by the tree-ring chronology].

This presents another major problem for Radiocarbon Dating because they then have to explain how the older heartwood [which is functionally dead – see above] acquired additional Carbon-14 so that Radiocarbon Dating could conclude it is younger than the outermost layers.

The Radiocarbon Dating of the first 250 years of the tree-ring chronology [inexplicably] ranges over 500 years [from over three hundred years too old to over 200 years too young].

1982 - J Klein et al - Calibration of radiocarbon dates - last 2000 years

Overall, the Radiocarbon Dating of the first 500 years of the chronology generates a giant horseshoe pattern which is totally inexplicable according to Radiocarbon Dating theory.

Furthermore, the only way the numerous [vertical] straight line dating sequences [red lines in the above diagram] can be generated is by Radiocarbon Dating [inconsistently] assigning different years to the same tree-ring year from the chronology samples.

Dating SNAFU

These problems would appear to be fatal for Radiocarbon Dating and it is extremely remarkable that a consensus was reached by Dendrochronology.

However, in the process of dating the Bristlecone Pine tree-ring chronology Radiocarbon Dating acquired a detailed knowledge of the tree-ring chronology that was equally fatal for Dendrochronology.

1982 - J Klein et al - Calibration of radiocarbon dates - Chronology

The present master chronology consists of two existent chronology units and 17 individual specimens.

The first chronology unit is made up of paired cores from nine trees in Methuselah Walk. These specimens comprise the second half (those with the most missing rings, and generally higher mean sensitivity and lower serial correlation) of the data in Table 1 (Ferguson 1968, Table 1).

The second unit is the Schulman Master, composed of 14 trees, which extends from A.D. 800 to 1954. It incorporates specimens from four sites in the White Mountains…

A 7104 Year Annual Tree Ring Chronology for Bristlecone Pine, Pinus Aristata, from the White Mountains, California – C. W. Ferguson – Tree-Ring Bulletin, Volume 29 (1969)
https://arizona.openrepository.com/arizona/bitstream/10150/259957/1/trb-29-03-04-003-029.pdf

As the Radiocarbon Dating progressed through the 40 individual Bristlecone Pine samples it would have become apparent that the apexes of the jagged, saw tooth “workshop data set” were primarily caused by the transition from one sample to the next [red lines below].

In other words, the whole construction of the tree-ring chronology was extremely suspect because the samples did not blend in smoothly with their neighbouring samples.

1982 - J Klein et al - Calibration of radiocarbon dates - Samples

Furthermore, Radiocarbon Dating could detect any tree-ring samples that had been reversed in the chronology based upon the Carbon-14 dates or by simple pattern matching in the chronology.

Reversed Sample

1982 - J Klein et al - Calibration of radiocarbon dates - reversed samples

However, it is also possible that the consensus was achieved by deliberately reversing samples because the other half of the jagged, saw tooth was represented by a tree-ring sample where the carbon-14 decayed at three times the normal rate or [more likely] there was a catastrophic event that temporarily inflated the level of atmospheric carbon-14.

Three Times Carbon-14 Decay

1982 - J Klein et al - Calibration of radiocarbon dates - x3 decay rate

It’s also possible to envisage a situation where Dendrochronology and Radiocarbon Dating reached a consensus to protect Uniformitarianism under terms of Mutually Assured Destruction.

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Gallery | This entry was posted in Catastrophism, Dendrochronology, Radiocarbon Dating, Uniformitarianism. Bookmark the permalink.

3 Responses to Dendrochronology – The MAD Carbon-14 Consensus

  1. Pingback: Dendrochronology: Disastrous Data | MalagaBay

  2. Pingback: A Carbon-14 Chronology | MalagaBay

  3. Pingback: Deranged Dating: In a Nutshell | MalagaBay

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