A Carbon-14 Chronology

A Carbon-14 Chronology

Mainstream Chronologies face major problems whenever they mix the artistry of dendrochronology with the science of radiocarbon dating.

These problems initially arise because numerous procedures in dendrochronology are based upon subjective human intervention:

Sample selection: which trees should be sampled out of the population?
Sample taking: which part of the tree should be sampled?
Missing rings: which rings should be deemed missing?
Double rings: which rings should be deemed double rings?
Triple rings: which rings should be deemed triple rings?
Sample rejection: which samples should be rejected?
Crossdating: how accurate does the crossdating have to be?
Site Master: how many samples are adequate based upon species and climate?
Bridging: how many rings must overlap based upon species and climate?
Bridging: how many samples are used to confirm a bridge?
Bridging: how accurate does the crossdating have to be?
Chronology: how many samples are adequate based upon species and climate?
Mixing: how are different species mixed into a chronology?

However, these initial problems are further compounded whenever dendrochronology is used to calibrate radiocarbon dating.

This is especially true when radiocarbon dating has been selectively employed to establish a tree-ring chronology that is subsequently used to calibrate radiocarbon dating.

These problems are clearly evident [especially in the first millennium AD] when the Bristlecone Pine and Irish Oak chronologies are compared.

Bristlecone Pines vs Irish Oaks

However, radiocarbon dating could become totally self-reliant by dumping dubious dendrochronological calibration and adopting a self-calibrating technique based upon the Δ14C values in the chronology.

Carbon-14 Chronology

The Δ14C values in a chronology can clearly be used to identify catastrophic gaps and catastrophic rises in carbon-14 [see above].

A proof-of-concept self-calibrating chronology [based upon the Irish Oak chronology] clearly demonstrates that third order polynomials provide a series of statistical calibration curves that highlight lacunae in the samples.

Carbon-14 Chronology Lacunae

This [first cut] self-calibrating chronology provides Irish archaeologists with a scientific foundation upon which they should be able to a) identify strata lacunae and b) date artefact layers in the strata.

Carbon14 vs Irish Oaks

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13 Responses to A Carbon-14 Chronology

  1. I’ve spent some time researching C14 decay issues etc and I was startled to read, say in “Radiochemistry and Nuclear Chemistry, Choppin, Rydberg et al, 2013”, Section 13.5a (Kindle edition)

    “It is reasonable to assume that the production of C14 in the atmosphere has been rather constant for at least a million years, which means that equilibrium exists between the rates of formation and decay of C14 in the atmosphere”.

    They also assume cosmic formation of C14 has been produced at a constant rate.

    These are, as Sir Humphrey might aver, courageous assumptions.

    It suggests that radiocarbon dating is only applicable to the last calendar assumption, 1582, and before that no one knows what the unit of time, meant physically; i.e. ‘t’ is a variable, not a constant, so if we add Juergen’s ideas about electric field magnitudes affecting radiogenic decay, the present day observations of variable radiogenic decay, then radiocarbon dating looks like being anything but absolute.

    That means that Gunnar’s proposed experiment may not answer the problem put by Mike Baillie.

    The surprising thing is that it strengthen’s Gunnar’s stratigraphic method – but as a geologist, I would expect to see photographed or mapped cross sections of the test stratigraphies, and age determination based on presence of artefacts etc.

    • malagabay says:

      I would expect to see photographed or mapped cross sections of the test stratigraphies, and age determination based on presence of artefacts etc.

      Totally agree…
      but finding stratigraphies on the internet is an “interesting” experience 🙂

      Hopefully, you will find my next posting more tangible…
      But in the meantime you might enjoy:

      Lacunar Amnesia in Archaeology

  2. I might make on additional comment based on field evidence related to me by a fellow diamond geologist. Some years back he found a lump of wood in one of the King George River (Kimberley region, Western Australia) kimberlites and had it dated. The kimberlites occur in Proterozoic sediments. The preliminary result was that the wood indicated a Cretaceous age, but when told of the location of the wood, the laboratory then decided that the wood was contamination. It helps to re-read Richard Milton’s chapters on dating in his controversial books as well, where radiometric date results are screened according to whether they fit the presumptions or not.

    REPLY
    Selection and Screening are a big problem…
    But hard to quantify when the results are not published.
    Regards
    Tim

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