New Altar Stone paper -- or is it?

There's a new article from Bevins, Ixer, Parker Pearson and co, relating to the Altar Stone and the debate about its origins. We have seen all the arguments before, so there is not much here that is new, apart from more sophisticated and automated measurements of the mineralogies of samples. Rob anticipated that I would not like this new article very much, and he is quite correct. Anyway, here are the details:

Constraining the provenance of the Stonehenge ‘Altar Stone’: Evidence from automated mineralogy and U–Pb zircon age dating.
Richard E. Bevins, Duncan Pirrie, Rob A. Ixer, Hugh O’Brien, Mike Parker Pearson, Matthew R. Power, Robin K. Shail
Journal of Archaeological Science 120 (2020), 105188---------------------------

Thanks to Rob Ixer for sharing this link providing 50 days' free access to the article. Anyone clicking on this link before August 16, 2020 will be taken directly to the final version of the article on ScienceDirect, which they are welcome to read or download.  No sign up, registration or fees are required.

The personalized Share Link:
https://authors.elsevier.com/c/1bI~J15SlTogWk

ABSTRACT

The Altar Stone at Stonehenge is a greenish sandstone thought to be of Late Silurian-Devonian (‘Old Red Sandstone’) age. It is classed as one of the bluestone lithologies which are considered to be exotic to the Salisbury Plain environ, most of which are derived from the Mynydd Preseli, in west Wales. However, no Old Red Sandstone rocks crop out in the Preseli; instead a source in the Lower Old Red Sandstone Cosheston Subgroup at Mill Bay to the south of the Preseli, has been proposed. More recently, on the basis of detailed petrography, a source for the Altar Stone much further to the east, towards the Wales-England border, has been suggested. Quantitative analyses presented here compare mineralogical data from proposed Stonehenge Altar Stone debris with samples from Milford Haven at Mill Bay, as well as with a second sandstone type found at Stonehenge which is Lower Palaeozoic in age. The Altar Stone samples have contrasting modal mineralogies to the other two sandstone types, especially in relation to the percentages of its calcite, kaolinite and barite cements. Further differences between the Altar Stone sandstone and the Cosheston Subgroup sandstone are seen when their contained zircons are compared, showing differing morphologies and U-Pb age dates having contrasting pop- ulations. These data confirm that Mill Bay is not the source of the Altar Stone with the abundance of kaolinite in the Altar Stone sample suggesting a source further east, towards the Wales-England border. The disassociation of the Altar Stone and Milford Haven undermines the hypothesis that the bluestones, including the Altar Stone, were transported from west Wales by sea up the Bristol Channel and adds further credence to a totally land-based route, possibly along a natural routeway leading from west Wales to the Severn estuary and beyond. This route may well have been significant in prehistory, raising the possibility that the Altar Stone was added en route to the assemblage of Preseli bluestones taken to Stonehenge around or shortly before 3000 BC. Recent strontium isotope analysis of human and animal bones from Stonehenge, dating to the beginning of its first construction stage around 3000 BC, are consistent with the suggestion of connectivity between this western region of Britain and Salisbury Plain.This study appears to be the first application of quantitative automated mineralogy in the provenancing of archaeological lithic material and highlights the potential value of automated mineralogy in archaeological provenancing investigations, especially when combined with complementary techniques, in the present case zircon age dating.

We have considered some of the research information in previous posts:

https://brian-mountainman.blogspot.com/2019/11/new-paper-on-stonehenge-sandstones.html

https://brian-mountainman.blogspot.com/2019/12/stonehenge-more-on-devonian-sandstones.html

https://brian-mountainman.blogspot.com/2018/12/new-paper-on-altar-stone-or-is-it.html

https://brian-mountainman.blogspot.com/2017/10/another-geology-paper-and-case-of.html

The Altar Stone is the one left of centre, just visible through the turf and largely hidden beneath two sarsens.  Have any of the "Altar Stone"samples really come from it?

As in the case of earlier papers by the same authors (with various other colleagues), I have no arguments with the reliability of the scientific analyses.  I am sure that the sample studies will have been done very carefully, with acceptable results.  The studies can, of course, be replicated by others if they so wish.  My gripe is that this is yet another piece of assumptive research, based upon two very questionable assumptions:

1.  The assumption that the six "Altar Stone" samples analysed (namely FN573, HM13, SH08, MS-1, MS-2 and MS0-3) did indeed come from the Altar Stone.  That is not demonstrated anywhere in the paper, and because of that, this whole thing might be just another wild goose chase. (As readers of this blog will know, there is great doubt as to the provenance of all of these samples.)

2.  The assumption that the Altar Stone -- and the other bluestones at Stonehenge -- were transported from Wales to Stonehenge by Neolithic tribesmen underpins this whole article.  Indeed, the bolstering of this hypothesis appears to be the main reason why this paper has been written.  However, there is no more evidence today for the human transport of the bluestones than there was a century ago,  and I am mystified as to why there was any necessity here to mention the bluestone transport controversy at all. Even the fantastical "bluestone quarries" get a mention, for no particular reason.   If the authors had stuck to the geology, this would have been a rather interesting and useful paper -- but as it is, it is spoiled by its descent into a fantasy-driven archaeological argument which is really rather peripheral.   A potentially good paper is transformed into a very bad one.

In the later part of the text, the authors concentrate on the case for sea transport versus the case for land transport of the bluestones -- an entirely futile argument and a waste of space for those of us who are looking for hard evidence rather than vague speculations.

One of the few positives to come out of this paper is the fact that the 2015 Rhosyfelin paper by Dyfed Elis-Gruffydd, John Downes and me is at least cited -- about time too, since up until now (for five years) this particular research team has existed in a state of denial about its very existence.  Well, they get there in the end.  At least, they have now acknowledged that, like more than 1,600 other people, they have actually read it.

Finally, there's this from the abstract:
"Recent strontium isotope analysis (analyses?) of human and animal bones from Stonehenge, dating to the beginning of its first construction stage around 3000 BC, are consistent with the suggestion of connectivity between this western region of Britain and Salisbury Plain."

I dispute that 100%.  The analyses do nothing of the sort, for reasons already enunciated in earlier posts.

Oh dear -- if only the geologists would stick to the geology........

One end of the Altar Stone, as revealed in the Atkinson excavation in 1958.