Saturday, 24 September 2022
Tuesday, 20 September 2022
There are some very out of date maps and theories circulating about the extent of the glaciers of the ice ages, much of it sadly spread by Stonehenge conspiracy theorists. It isn't hard to make sure only the latest and best information is used as the basis for any discussion. Here are a couple of pointers.
The Devensian British-Irish Ice Sheet
The Devensian British-Irish Ice Sheet was a large mass of ice that covered approximately two thirds of Britain and Ireland around 27,000 years ago. All of Scotland and Ireland, most of Wales, and most of the north of England was underneath the ice sheet during the Last Glacial Maximum. This ice sheet retreated and shrank after 27,000 years ago, and had completely disappeared by 11,300 years ago
For a recent comprehensive review: Chiverrell, R.C. and Thomas, G.S.P. (2010), Extent and timing of the Last Glacial Maximum (LGM) in Britain and Ireland: a review. J. Quaternary Sci., 25: 535-549. https://doi.org/10.1002/jqs.1404
And for the very latest including information about the Welsh Ice Cap and the Preseli Hills please see this chapter:
Philip D. Hughes, Chris D. Clark, Philip L. Gibbard, Neil F. Glasser, Matt D. Tomkins, Chapter 53 - Britain and Ireland: glacial landforms from the Last Glacial Maximum, Editor(s): David Palacios, Philip D. Hughes, José M. García-Ruiz, Nuria Andrés, European Glacial Landscapes, Elsevier, 2022, Pages 407-416, ISBN 9780128234983, https://doi.org/10.1016/B978-0-12-823498-3.00033-9. (https://www.sciencedirect.com/science/article/pii/B9780128234983000339)
Friday, 2 September 2022
"A giant bluestone erratic just discovered near Mumbles, on the south Gower coast, has been hailed as one of the most important glacial discoveries of the last century since it proves beyond doubt that the Irish Sea Glacier was capable of carrying large monoliths of dolerite rock from Pembrokeshire up the Bristol Channel towards Stonehenge."
And so on...
Green dolerite erratic carried on Irish Sea Glacier from Preseli to Mumbles c 19000 years ago. Stone such as this was used to construct Stonehenge.
Thursday, 1 September 2022
Current Archaeology's article on the rediscovery and analysis of Stonehenge Bluestone samples found in museums - https://the-past.com/feature/victorian-gifts-new-insights-into-the-stonehenge-bluestones/ - features a fascinating labelled specimen from the Altar Stone in Salisbury Museum. This fragment ties other samples that can be fully analysed back to the Altar Stone and hence allows those samples to be used to hopefully determine in the future the source of the stone.
Linking the sample to a documented excavation gives it provenance and trustworthiness.
Current Archaeology has a fascinating article about the "rediscovery of a series of rock samples collected during the Victorian period has allowed new analysis of some of the stones of Stonehenge. By Rob Ixer, Richard Bevins, Nick Pearce, and David Dawson".
One of the more interesting parts is the final putting to bed of the theory that the so-called Newall Boulder is a glacial erratic. A theory that was first raised in 1991 by G A Kellaway in "The older Plio-Pleistocene glaciations of the region around Bath." - Hot Springs of Bath, pp 243-41