Exit Wales!

[Digit]

http://www.britarch.ac.uk/ba/ba109/interim.shtml

Another piece of dogma bites the dust!

Roy.

[Minimalist]

I thought the Preseli hills were identified as the source ages ago?

These guys miss that memo?

[Digit]

Initially Min the stones were assumed to have come from a site in Wales due to visual inspection. Eventually a limited number of stones were subject to chemical analysis, this resulted in a more than one site in Wales being a match.
This latest is an extension of that.
At the time of the previous analysis I pointed out here that multiple sites strongly suggested that the stones were erratics, as mining from various sites greatly complicated the logistics of delivery to the Plain.

Roy.

[Minimalist]

Does this mean the glaciers are out?

[Rokcet Scientist]

Does this mean the glaciers are out?

The glaciers of which glacial? Taking into consideration that they were dynamic systems: they grew and receded every year.

[Digit]

Quite the opposite Min, and RS is spot on, if they were moved away from their origins by ice we have no way of telling when. The last GM will have wiped out much evidence of previous glaciations.
Lowland England has but two major river systems, the Thames and the Severn. Both are supposed to have been formed by melt water run off during the last GM, in view of the depth and width of their valleys, and the known position of the ice advance, that seems certain for the Thames. The Thames runs E/W, there is problem with the Severn if you look at maps of the ice sheet. The Severn runs N/S.
I ran a simulation of the ice advance yesterday and one fact was missing, the assumption that is taught is that the ice moved south from the arctic. Unlikely I think, as temps fell the high peaks would have produced glaciers long before arctic ice reached them, and the Severn drains the mountains in North Wales.
This suggests that the Severn probably was a glacier long before it was a river. The moraines near me clearly show that the the glaciers on the western side of the mountains moved south and west, thus moving any rocks away from England. On the eastern side of the mountains the matter is less certain, depending on whether the Severn was water cut or glacial.
These are the reasons that the idea of man hauling of the Blue stones was suggested, there is no direct evidence.
This information is, as RS pointed out, ignoring of any previous glaciations.
To man haul from numerous sites, when none were exhausted, seems pointless as that would require more roads/tracks and possible docking areas.
The logical deduction must be that the stones were a glacial assemblage that the constructing gangs helped themselves to.

Roy.

[Minimalist]

As I recall the suggestion it was that the glaciers carried exactly the right number of stones of more-or-less the proper size and deposited them on the Salisbury Plain....and no where else.

That seems to be asking a lot of a glacier.

[Digit]

Sounds more like a delivery service to me Min!
Few erratics now exist in Britain other than in barren areas, over the years farmers have destroyed them.

Roy.

[Minimalist]

Certainly not the post office.

[Rokcet Scientist]

The last GM will have wiped out much evidence of previous glaciations.

...insofar as the last GM covered the previous glaciations' extent! End moraines and ground moraines of earlier glaciations that extended further could be identifiable.

[Digit]

that extended further could be identifiable.

Agreed, I have tried to discover the extent of earlier glaciations but without success.

Roy.