Re: The bluestone debate | Forum — The Modern Antiquarian

Stonehenge and its Environs 134

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The bluestone debate

tiompan Dec 18, 2008 17:24:36

Replying to mountainman

mountainman wrote:

Thorpe and Williams-Thorpe (Antiquity 1991) looked at all of the UK sites and found that the megalith builders used stones from up to 2 km away quite often, but that there was no case of stones being carried more than 5 km. So let's refer to all of these sites as "using locally-sourced stones."

I have just had a quick skim through the Thorpe & Williams Thorpe paper and it is apparent that they merely done a quick survey not dissimilar to what archaeologists had noted since the early 20th C. i.e. that megalithic monuments are confined to areas where there are convenient local outcrops or rocky areas in general . They have not done a survey of each stone circle and the lithogeochemistry of each component ,an immense task and probably unnecessary as the basic assumption of the earlier archaeos is probably broadly correct that the builders used local materials exactly as you would expect . However there are some monuments where there is obviously not the case but as all these cases are in areas that have seen some ice cover or extreme glaciation they take the view that this explains all the anomalies . They are by no means as certain as you though in that they say “ most stone circles in Britain appear to have been constructed from local materials “ and “within the glaciated areas of N Europe it is more difficult to interpret because of the possibility of glacial transport “( my italics ) .They do mention Old Keig saying “the Grampian area has experienced repeated extensive glaciations ; the case for human transport , rather than selection from locally deposited glacial till is unproven “ I wonder , if by placing Old Keig within the Grampian area they are aware of the huge differential in glaciation in that political zone which contains the Cairngorms ,which were heavily glaciated but further north had an entirely different experience ( see “The Glacial Period in Aberdeenshire and the Southern Border of the Moray Firth “ Thomas Jamieson .) resulting in the previously mentioned lack of erratics . I doubt that you will find a local geologist claiming the recumbent to be an erratic. One sacred cow may have been taken towards to the slaughter house but it may be replaced by another , if any reasonable suggestion is met by “it was probably an erratic “ it leads to a conclusion that the inhabitants of previously glaciated northern Europe were somehow causally connected to these events resulting in an inability to move megaliths long distances whilst their neighbours to the south , possibly not lacking in the mineral deficiencies

mountainman Dec 19, 2008 10:11:56

Replying to tiompan

That's all fair enough. Of course we can never be certain about these things -- but with my background, I will always look first for a natural explanation and then -- if there is some incontrovertible piece of evidence against it -- move on to an alternative. Quite often, as Olwen Williams-Thorpe and colleagues have pointed out, stones in megalithoic monuments assumed to have come from a long way off turn out not to have come very far at all. We need to know exact provenances for stones (sadly, that's not that easy in many cases without detailed geochemistry of the type that has now differentiated the ORS Cosheston Beds from the Senni Beds and sorted out the source of the Altar Stone) and also ice flow directions. (Other processes can move big stones too -- tsunamis, landslides, drifting ice floes, jokulhlaups etc -- and in some cases they migh be important.) By the way, Jamieson was writing a century ago -- the idea of "ice-free Buchan" has now been discredited. It was glaciated, but the ice that covered it was probably cold-based, and its landscape effects were limited.

tiompan Mar 2, 2017 08:51:27

Replying to tiompan

Update on the possible provenancing of the recumbent .

The original analysis of the recumbent from Childe's excavation was done Dr R.Campbell he suggested “ sillimanite gneiss” . He added “The recumbent stone is not of local origin .Similar rocks occur in the Don valley between Kemnay and Tilliefourie .” There is no detail explaining his analysis or mention of thin sections .
It turns out there was an NMS geological survey in 2006 (not mentioned in Canmore ) which disagreed with the original findings concluding that the recumbent was “foliated granite “ .

I had contacted the best and he had very kindly offered a cut price analysis of thin sections , this would have solved a big part of the puzzle , but no removal of material is allowed .
So , a bit of an impasse .