Sunday, 2 October 2022

The latest scientific consensus on Stonehenge and Glacial Transport - there is no evidence of a link

There seems to be some confusion as to what the latest scientific consensus by the relevant experts in glaciation is with regards to Stonehenge.

TL;DR summary:  They acknowledge their models aren't quite working with how far the ice spread out into the Celtic sea, but when they tweak the current model to correct that it brings ice down into the south west of England where there is no evidence for it apart from a hypothesis of glacial erratics at or on their way to Stonehenge. They prefer the hypothesis that they are missing an input in their model and if that was corrected the model would match the reality better, which doesn't include glaciers in the south west of England.   

Maximum Glaciation

The relevant paragraph:

An egregious mismatch occurred at 26 ka, where the modelled grounding line position of the Irish Sea Ice Stream fell 150 km behind that indicated by the geological evidence (minimum reconstruction, Fig. 6; Scourse et al. 2021). We experimented with various nudges to the model to try and prevent this underrun but they resulted in significant overruns of other parts of the ice sheet, notably with the SW Peninsula of England (Cornwall and Devon) and much of the English Midlands becoming glaciated. The final choice of model run (Fig. 6) is therefore a compromise that mostly fits the wider empirical limits, but underruns in the Celtic Sea. The alternative choice of accepting a model run that reached the shelf edge in the Celtic Sea but also glaciated the SW Peninsula and parts of the English Midlands would have interesting implications for the long-standing hypothesis that some of the stones of Stonehenge may have been transported, at least partway as glacial erratics (e.g. Judd 1902; Scourse 1997; John 2018; Pearson et al. 2019). Although this may indeed be accommodated by earlier more extensive glaciations, we suggest however, that a process, forcing, or feedback is missing in the numerical modelling we present here and that once discovered would enable sufficient ice advance in the Celtic Sea without exceeding ice limits elsewhere. For example, Scourse et al. (2021) suggest that a non-steady oscillation (surge) arose as a release from the build-up of ice behind a topographic constriction in the Irish Sea. We further speculate that the drainage of lakes on the ice stream surface, or floods from subglacial lakes, may have temporarily facilitated faster ice flow and ‘over-extension’ of the ice margin by locally increasing basal lubrication. 


Clark, C.D., Ely, J.C., Hindmarsh, R.C.A., Bradley, S., Ignéczi, A., Fabel, D., Ó Cofaigh, C., Chiverrell, R.C., Scourse, J., Benetti, S., Bradwell, T., Evans, D.J.A., Roberts, D.H., Burke, M., Callard, S.L., Medialdea, A., Saher, M., Small, D., Smedley, R.K., Gasson, E., Gregoire, L., Gandy, N., Hughes, A.L.C., Ballantyne, C., Bateman, M.D., Bigg, G.R., Doole, J., Dove, D., Duller, G.A.T., Jenkins, G.T.H., Livingstone, S.L., McCarron, S., Moreton, S., Pollard, D., Praeg, D., Sejrup, H.P., Van Landeghem, K.J.J. and Wilson, P. (2022), Growth and retreat of the last British–Irish Ice Sheet, 31 000 to 15 000 years ago: the BRITICE-CHRONO reconstruction. Boreas.

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