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Theory on moving the Bluestones |
jonm
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|  Posted 22-09-2011 at 12:55
Perhaps it might be worth considering how our Victorian ancestors approached the same problem?
Heavy loads, when there is little or no automation, can be moved either by barge or by rail. Barge works well for repetitive tasks but you need the river to be there or to create it.
Rail can be created for one-off tasks and is frequently used today for manoeuvring heavy loads (such as safes) when there is no crane access (I've done it myself this way)
A rail can be created using logs: Probably multiple logs. A stable wheel can be created if you have encased your stones to form a cylinder. All the better if the cylinder has grooves that can 'fit' onto the rails in the same way that modern rails do.
If a first stone is rolled manually to the top of a hill, it can be used as a counter-weight to roll the second up (as it goes down, the rope winds on it; the rope unwinds on the second stone). The second stone, now at the top, is then used as the counterweight for the third and so on.
Effectively, you only need to roll one stone, preferably the lightest, manually up hills. And it needs a bit of care getting the last stone down. You also need to plot your course very carefully around most of the larger hills so that the rope is not too long: This would extend the journey significantly so it's not an option if you can use the sea or rivers easily.
The effective ground bearing pressure needs to be reduced to less than 10kPa to allow rolling over boggy ground: Preferably much less than this. If a complete cylinder assembly weighs in the region of 30kN (3 tonnes), and the diameter is made to about 2.5 metres for a 3 metre long stone, the required minimum contact area for 10kPa becomes about 3 square metres: Logs placed parallel to the direction of travel, rather than as rollers, will easily distribute this load over bad ground without causing excessive ground deformation.
Jon
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PAB
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| Posted 26-09-2011 at 01:27
I am normally cautious about joining discussions in the 'forum dimension', but a couple of comments need comments..
First, in reply to SecretsoftheSunSects who said "Clearly no one doubts that the rocks were moved great distances by boats, possibly up to the edge of the stone circle."
...actually, many very thoughtful people are yet to be convinced that the rocks got to the general vicinity of Salisbury Plain by boats. I am not saying they weren't, but it is important to avoid statements which could be taken as suggesting that this has already been proven.
Secondly, Jonm used an interesting phrase: "Perhaps it might be worth considering how our Victorian ancestors approached the same problem?"
...this raised the question in my mind as to whether the builders of Stonehenge really did have the 'same problem' as our Victorian ancestors? If jonm means how to manoeuvre the stones into position once they got to the locality, I can see what s/he means.
It is important to remember however that the majority of the distance covered by the stones which came from South Wales might have been courtesy of mother nature in the form of glacial movement, leaving only the final miles to be managed by 'us'.
Even if our ancient ancestors did have a hand (or many) in helping some stones get from S Wales to the Salisbury Plain, I rather lean towards Feanor's view of this being a generation-long activity.
For now, I ask only that we do not assume that we know the answers, so leave room (& respect) for other possibilities.
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SecretsoftheSunSects
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| Posted 26-09-2011 at 06:21
PAB
I would agree, nothing is 100% and the sites took many generations to build. We make our best guesses based on the evidence, the use of boats throughout the ancient world is telling. The most critical to me would be that boat found in a neolithic quarry just outside Birmingham.
If people do not fix on common sense they tend to skip rather happily to magic beans and MMEs.
As for the last few meters of maneuvering the rocks, I like ice and snow, I just added it to the pot because it reduces the loads. Just look at a sled and reindeer. I know that will generate the odd idiot Santa comment, but cold winters were never far away and this moving technique would leave little if any evidence at all.
I notice Jon did not add the friction needs on that one in the interesting post above, they are just tiny, look at a skater. The heavier the stone the easier it slides as opposed to the mechanical methods.
Chris
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On 2011-09-26 01:27, PAB wrote:
I am normally cautious about joining discussions in the 'forum dimension', but a couple of comments need comments..
First, in reply to SecretsoftheSunSects who said "Clearly no one doubts that the rocks were moved great distances by boats, possibly up to the edge of the stone circle."
...actually, many very thoughtful people are yet to be convinced that the rocks got to the general vicinity of Salisbury Plain by boats. I am not saying they weren't, but it is important to avoid statements which could be taken as suggesting that this has already been proven.
For now, I ask only that we do not assume that we know the answers, so leave room (& respect) for other possibilities.
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jonm
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| Posted 27-09-2011 at 10:18
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| ...this raised the question in my mind as to whether the builders of Stonehenge really did have the 'same problem' as our Victorian ancestors? If jonm means how to manoeuvre the stones into position once they got to the locality, I can see what s/he means. |
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I doubt the glacial theory: There appears to be little evidence of sufficient glacial border deposition:
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[ This message was edited by: jonm on 2011-09-27 10:23 ]
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tiompan
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| Posted 27-09-2011 at 11:04
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On 2011-09-27 10:18, jonm wrote:
Quote:
| ...this raised the question in my mind as to whether the builders of Stonehenge really did have the 'same problem' as our Victorian ancestors? If jonm means how to manoeuvre the stones into position once they got to the locality, I can see what s/he means. |
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I doubt the glacial theory: There appears to be little evidence of sufficient glacial border deposition:
Source
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[ This message was edited by: jonm on 2011-09-27 10:23 ]
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To be fair to the glacial theory proponents they do not suggest that glaciation extended to the Stonehenge area . We are also learning more about the extent of the ice e.g. http://www.sciencedirect.com/science/article/pii/S0277379105000491
George
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jonm
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| Posted 27-09-2011 at 13:42
Fair comment: I guess it's possible. But if the glacial deposition were not nearby, then they would still have to move the rocks over some considerable distance.
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jonm
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| Posted 27-09-2011 at 13:54
Quote:
| I notice Jon did not add the friction needs on that one in the interesting post above, they are just tiny, look at a skater. The heavier the stone the easier it slides as opposed to the mechanical methods. |
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The pressure of the skate causes ice to liquify around the pressure points: If this is a sled or a skate on a solid surface (ice) then the friction can be minimal. However, a large rock on snow would be a different story: Heavily re-frozen snow can carry perhaps in the region of 5kpA (rough estimate) so the sled would have to be huge.
There's also the slight problem that the stones were constructed towards the end of a climatic maxima (ie a warm period). The winters were, apparently, colder but summers considerably warmer: It would have been a very short window of time for the snow to fall sufficiently and to then produce deep compacted refrozen snow.
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tiompan
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| Posted 27-09-2011 at 14:31
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On 2011-09-27 13:42, jonm wrote:
Fair comment: I guess it's possible. But if the glacial deposition were not nearby, then they would still have to move the rocks over some considerable distance.
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That was always going to be the case but it removes the transporters association with Presceli .
George
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jonm
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| Posted 27-09-2011 at 15:23
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On 2011-09-27 14:31, tiompan wrote:
That was always going to be the case but it removes the transporters association with Presceli .
George
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True, but it means they would still have had a very large distance to cover over land: Probably longer than if they had added on the deep river/sea route from Presceli (given the apparent terminus of the glaciers elsewhere). I understand it's a felsic rock, so one attraction of that rock type would be the low density. A disadvantage would be the fragility of the rock.
Allowing say 4 tonnes for a larger rock (40kN), say 3 metres long, the equivalent balance volume of pine is about 7.5 cubic metres: So the encasement diameter only needs to be about 2 metres plus for a timber-encased sandwich assembly to float. Presceli has the added bonus of a river or two relatively close to source and in the right direction to aid the rolling or floating.
Encasing also has the advantage that you can afford to be a little less careful when moving the rocks.
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tiompan
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| Posted 27-09-2011 at 16:01
The argument is that the glaciation reached Somerset and geomorphologists think that possible ,in which case the distance as the crow flies is decreased from 140 miles to 40 miles plus the dissociation with Preseceli .
George
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On 2011-09-27 15:23, jonm wrote:
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On 2011-09-27 14:31, tiompan wrote:
That was always going to be the case but it removes the transporters association with Presceli .
George
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True, but it means they would still have had a very large distance to cover over land: Probably longer than if they had added on the deep river/sea route from Presceli (given the apparent terminus of the glaciers elsewhere). I understand it's a felsic rock, so one attraction of that rock type would be the low density. A disadvantage would be the fragility of the rock.
Allowing say 4 tonnes for a larger rock (40kN), say 3 metres long, the equivalent balance volume of pine is about 7.5 cubic metres: So the encasement diameter only needs to be about 2 metres plus for a timber-encased sandwich assembly to float. Presceli has the added bonus of a river or two relatively close to source and in the right direction to aid the rolling or floating.
Encasing also has the advantage that you can afford to be a little less careful when moving the rocks.
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jonm
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| Posted 27-09-2011 at 16:38
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| The argument is that the glaciation reached Somerset and geomorphologists think that possible ,in which case the distance as the crow flies is decreased from 140 miles to 40 miles plus the dissociation with Preseceli . |
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Sound reasonable. Are there extensive deposits of smaller bluestone boulders in Somerset?
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tiompan
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| Posted 27-09-2011 at 17:25
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On 2011-09-27 16:38, jonm wrote:
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| The argument is that the glaciation reached Somerset and geomorphologists think that possible ,in which case the distance as the crow flies is decreased from 140 miles to 40 miles plus the dissociation with Preseceli . |
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Sound reasonable. Are there extensive deposits of smaller bluestone boulders in Somerset?
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I don't know for sure but don't believe so .
george
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jonm
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| Posted 27-09-2011 at 18:47
I don't know for sure but don't believe so .
Probably works against the glacier theory: If there a large bank of bluestone deposits somewhere, then you would probably find the remains of the larger bluestones as part of the package, deposited up-steam within other glacier deposits (the bigger ones tend to rumble along at the bottom of the glacier from memory).
The big ones and mixed boulder areas provide terrible problems for house foundations because they tend to be sited below and in the silty clay deposited as the glacier retreats: So one side of a house can settle and the other stay exactly where it was. On some streets at the boulder boundary, almost every house has to be underpinned.
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ledgehammer
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| Posted 27-09-2011 at 19:27
Hi
I added this to another topic:
Extreme masonry
The bit that interested me was the image which seems to be showing the ancient egyptions using buckets of something i.e a lubricant as well as a lot of brute force, the image seems to be broken, I am not sure why.
Tom
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tiompan
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| Posted 27-09-2011 at 19:30
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On 2011-09-27 18:47, jonm wrote:
I don't know for sure but don't believe so .
Probably works against the glacier theory: If there a large bank of bluestone deposits somewhere, then you would probably find the remains of the larger bluestones as part of the package, deposited up-steam within other glacier deposits (the bigger ones tend to rumble along at the bottom of the glacier from memory).
The big ones and mixed boulder areas provide terrible problems for house foundations because they tend to be sited below and in the silty clay deposited as the glacier retreats: So one side of a house can settle and the other stay exactly where it was. On some streets at the boulder boundary, almost every house has to be underpinned.
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But you do find erratics of Ulster white Limestone in Somerset .
george
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sem
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| Posted 27-09-2011 at 23:31
YOU LUCKY, LUCKY THINGS
We in Wales have to wait for days until we find out who is the architect of stonehenge, assuming of course, fifteen hefty blokes haven't been pushing a pig's bladder around in the meantime.
PS What do you call a Welshman with a Rugby World Winner's Cup Medal?
Over to you Cerrig!
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jonm
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| Posted 28-09-2011 at 10:08
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| But you do find erratics of Ulster white Limestone in Somerset .
george |
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Sure, but the bigger bits, and lots of smaller bits of Ulster white, still appear to be there. Glaciers don't appear to have any selection process where they pick up only stonehenged sized pieces of rock.
OTOH, it's possible that the bluestones were carved from one single large anomaly? There was an inuit tribe that, on discovery, proved to be using metal knives. Turned out to be from meteorites:
Anomaly
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jonm
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| Posted 28-09-2011 at 10:20
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| The bit that interested me was the image which seems to be showing the ancient egyptions using buckets of something i.e a lubricant as well as a lot of brute force, the image seems to be broken, I am not sure why. |
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Hi Tom
That looks a good way to do it, particularly for very large stones
[ This message was edited by: jonm on 2011-09-28 10:20 ]
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