Isotopes

In general, the chemical elements appear on earth with atoms of the same weight – with the same number of protons and neutrons in their nuclei. Carbon is mostly Carbon-12, Oxygen is mostly Oxygen-16, and Hydrogen is mostly Hydrogen-1. However, as we know only too well from radiocarbon dating exercises, atoms of different weights also occur naturally, such as Carbon-14. Many of these gradually decay, either into the more normal kind or into a different element altogether, but some are stable, such as Oxygen-18, which occurs at the rate of about one in every five hundred Oxygen atoms, and Hydrogen-2, also called Deuterium, which occurs at the rate of about one in every ten thousand Hydrogen atoms.¹ Thus a molecule of water, H₂O, although mostly of a molecular mass of 18, can weigh as much as 22, which is significantly heavier and affects its behaviour. The heavier molecule requires more energy to evaporate, but having done so, precipitates more easily too. This creates an imbalance of ¹⁸O/¹⁶O and ²H/¹H ratios around the world, and in the organisms which absorb water (and carbon dioxide) and lock it in the cellulose of their structure.

The ¹⁸O/¹⁶O and ²H/¹H ratios are reported in terms of their deviation from a standard, of which there are several. In general plant cellulose contains more ¹⁸O and less ²H than the standards. The factors which affect the precise values of these ratios are not well understood, but, among others, they certainly seem to be climate related. The colder the climate the less the ¹⁸O deviation, and the more the ²H deviation from the standard, and the hotter the climate the reverse. As will be seen, Egyptian textiles deviate further from the ¹⁸O standard than Polish ones.

As long ago as 1984, Michael deNiro and Jim Druzik of STuRP proposed measuring “the isotope fractions of ¹⁸O/¹⁶O and D/H (²H/¹H) from the linen cellulose” which “should provide information about the climate where the flax was grown.” Unfortunately this project did not come to fruition, but DeNiro and Druzik, with colleagues Leonel Sterberg and Bruno Marino, carried out a comparison exercise using non-Shroud textiles as a demonstration of proof-of-concept.² They tested 29 samples of linen from eleven countries, with results than can be plotted like this:

The first thing we note is that there is a significant overlap between Belgium/France and Israel, so if a Shroud test should give a result in that area, it would be impossible to claim on isotopic ratios alone that it was from one area or the other.

Fast Forward to 25 March 2024, and an article in an Italian blog called Stilum Curiae, belonging to Marco Tosatti, quoting a report by Bill Meacham, every authenticist’s go-to archaeologist, on an isotopic analysis of various textiles, including, this time, some threads from the Shroud. The results are simplified for a general readership, and expressed as a graph similar to that above:

This graph, and the explanation of how it was achieved, has now been published in the Newsletter of the British Society for the Turin Shroud (Issue 99, Summer 2024), under the title: ‘Shroud Isotopes Reveal Probable Near East Origin,’ by Bill Meacham.³ I think “probable” is rather an optimistic authenticist assessment – “possible” would be rather more realistic – but think that this kind of experiment could be diagnostic if further investigation is carried out.

For a start, only one (the upper one) of the two points labelled ‘Europe outlier’ is an outlier. There is no statistical justification to suggest that the lower one is anything but a regular member of the ‘Europe’ set, and the Shroud sample lies snugly amongst it. By comparison with the earlier study, one might instead wonder about Meacham’s Israeli results found in that area. Excluding the Israeli results and the outlier, all the points fall into two well defined separate groups, Egypt and Europe. Each of these groups contains two Israeli results, with one between the two less obviously associated with either. It would be interesting to check the provenance of these Israeli samples to see if we can infer some environmental reason for the distribution.

It is also interesting that Meacham’s overall pattern is very similar to that of the 1988 investigation, with the Israeli data overlapping both the Egyptian and the European data. Even though the testing procedures were different and the standards used were different, the simple shapes of the two patterns are too similar for there not to be some correlation between the two:

By this comparison, Meacham’s Shroud (green), and two Israeli (red) samples sit firmly in the European (yellow) group. If the Israeli samples are truly from Israel, then the Shroud could be Israeli too, but to claim that it is “probable” that the Shroud is from the Near East is unjustified on the basis of this analysis.

To be fair Meacham partially acknowledges this: “The isotope results are not proof of origin, however, as there is slight overlap of a couple of samples from Western Europe with those of Israel. Similar slight overlap occurred also in the baseline testing done in 1988. Various scenarios can account for the anonymous results: linen fibre imported from another country, irrigation using water from deep ground, or contamination due to pest repellent or preservative.”

Nevertheless, I do think this is a worthwhile avenue which has not been pursued before, and that further investigation could prove definitive.

1 There also exist Hydrogen-3 and Oxygen-17, but these will not concern us here.

2 ‘Relation between D/H ratios and ¹⁸O/¹⁶O ratios in Cellulose from Linen and Maize – Implications for Paleoclimatology and for Sindonology,’ Michael deNiro et al., Geochimica et Cosmochimica Acta, 1988

3 ‘Shroud Isotopes Reveal Probable Near-East Origin,’ William Meacham, Newsletter of the British Society for the Turin Shroud, Issue 99, 2024