Articles to 2022-12-18

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First the link to this week’s complete list as HTML and as PDF.


Powell et al. from last week’s list finally offer a comprehensive table of analyses of the Uluburun tin ingots. Such fully reported data have become rare these days. But the analysis they offer is somewhat strange. Of the four main isotopes of lead only the minor (1.4 %) Pb204 is primordial, the other three are (mainly) radiogenic. Pb208 is the end point of the Th232 series, Pb206 of U238 and Pb207 of U235. Of course the ratio of radiogenic to primordial lead depends not only on geologic age but also on the highly variable rate of impurity by the mother elements. Thus this ratio is meaningless in itself and only the regression gradient can be interpreted (Berger 2020, 2021, and 2022). Of course this regression in itself assumes all samples to come from the same source with one single common age. The provenance being the open question to be ascertained, this reasoning is blatantly circular.

On the other hand the ratios between the three radiogenic isotopes do provide a rather reliable fingerprint in spite of the error introduced by the unknown (but small) primordial component. A good world wide overview is shown in Dayton 2003.

A number of samples around the Pb207/206 = 0.83 mark show quite high values of lead contamination (click to enlarge).

lead concentrations

(N.B: The unit of ppm is a guess. The source table lacks both a caption and units.) All these also have high values of other trace elements so it isn’t certain, where the lead comes from. Contrary to expectation these are not outliers in the lead isotope diagram but they all cluster quite tightly.

lead isotope ratios

As expected the tin isotopes tell us nothing. The only area of spread is with the highly contaminated samples.

tin isotopes

Compared to the world wide distribution all the lead isotope ratios fall into the extreme low end (compare Dayton 2003). The only probable source for values like that is in Uganda and neighbouring regions. All the rest of the Uluburun cargo could plausibly be sourced in Egypt. So it would make sense for the tin coming from there too. This would make it a point to point journey with a single source and destination, totally in line of what written sources tell us about international relations at the time. Purely mercantile exchange without state sponsorship came much later in the Iron Age.

Berger 2020
Daniel Berger, Gerhard Brügmann & Ernst Pernicka, Zum Stand der Zinnforschung: Neue Erkenntnisse zu Zinnherkunft und -handel anhand von Isotopen- und Spurenelementanalysen spätbronzezeitlicher Zinnbarren. Metalla (2020), Sonderheft 9, 192–195.
Berger 2021
Daniel Berger, Gerhard Brügmann, Ernst Pernicka & Jörg Stolz, Naturwissenschaftliche Untersuchungen zur Erhaltung, Zusammensetzung und Herkunft der frühbronzezeitlichen Zinnperlen aus Schwabmünchen und Buxheim. In: Stefanie Berg & Carola Metzner-Nebelsick (Hrsg.), Eine einmalige Zinnperlentracht der Frühbronzezeit aus Bayern, „Powerdressing“ vor 4000 Jahren. Inhalte – Projekte – Dokumentationen 23 (Lindenberg 2021), 117–140.
Berger 2022
Daniel Berger, Quanyu Wang, Gerhard Brügmann, Nicole Lockhoff, Benjamin W. Roberts & Ernst Pernicka, The Salcombe metal cargoes: New light on the provenance and circulation of tin and copper in Later Bronze Age Europe provided by trace elements and isotopes. Journal of Archaeological Science 138 (2022), 105543, 1–28.
Dayton 2003
John E. Dayton, The problem of tin in the ancient world, (Part 2). In: Alessandra Giumlia-Mair & Fulvia Lo Schiavo (Hrsg.), Le probleme de l’etain a l’origine de la metallurgie – The Problem of Early Tin, Acts of the XlVth UISPP Congress, University of Liege, Belgium, 2–8 September 2001. BAR International Series 1199 (Oxford 2003), 165–170.


Smerdon finds a slight impairment in the performance of chess players through mask wearing. This may be psychological or physiological. If the latter, the effect should get worse with time, if the former, it should wear off through habituation. In his results Smerdon finds the latter to be the case. So whatever positive impact masks may or may not have, at least their imposition does no harm.


Baker et al. offer only models, but proven and well-founded ones. In spite of their significant short-term effects, prolonging the non-pharmaceutical interventions will have no durable benefit for most infectious diseases.


I see no benefit to the current fracking frenzy, mostly because I see no sense in squandering a large new-found resource within little over a decade. That said neither Clark et al. nor Li et al. are very convincing. With all the uncertainties inherent in epidemiology their effect sizes are far too small, in the case of Clark et al. not even statistically significant, to be taken seriously.

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