A collection of informative videos put online by the “CPIE Val de Vilaine – Association Nature et Mégalithes”
Wednesday 26 July 2023
Tuesday 25 July 2023
La construction du dolmen de Menga, Mantequera, Málaga
Dolmen de Menga (Official Site)
The Dolmen of Menga (Spanish: Dolmen de Menga) is a megalithic burial mound called a tumulus, a long barrow form of dolmen, dating from 3750–3650 BCE approximately. It is near Antequera, Málaga, Spain. It is one of the largest known ancient megalithic structures in Europe. It is 27.5 metres (90 ft) long, 6 metres (20 ft) wide and 3.5 metres (11 ft) high, and was built with thirty-two megaliths, the largest weighing about 180 tonnes (200 tons). Wikipedia - https://en.wikipedia.org/wiki/Dolmen_of_Menga
Text used under the Creative Commons Attribution-ShareAlike License 4.0
Human Transport of Megaliths - Experimental Evidence
The Bougon burial mounds are a group of five burial mounds constituting a Neolithic necropolis located in the commune of Bougon in the Deux-Sèvres department. The first monuments were built in the 5th millennium BC but the site was used until the middle of the 3rd millennium BC. A museum of prehistory, housing rich archaeological collections from excavations in the region, was built by the Departmental Council of Deux-Sèvres inside the archaeological park encompassing the site.
By Jochen Jahnke, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=12221012
The archaeological park which integrates the necropolis also contains several educational spaces intended to evoke the construction of megaliths , through the experiments carried out between 1979 and 1998 in Exoudun-Bougon, and the large Neolithic collective habitat of the Fief Baudouin discovered in Airvault .
- The text and photos are translated from the French version of Wikipedia entry for the site and used under under CC BY-SA 4.0 -
1979 experiments
These experiments were directed by Jean-Pierre Mohen. For details see Jean-Pierre Mohen and Chris Scarre (with the participation of F. Bouin, E. Cariou, P. Chambon), The tumulus of Bougon (Deux-Sèvres): Megalithic complex from the 5th to the 3rd millennium , Paris, Errance 2002 (ISBN 2-87772-240-6 and 978-2-87772-240-7 )
The first experiment concerned the extraction of a large megalithic slab of 3 m by 2.50m from a rocky outcrop located on the Chaumes plateau in Exoudun . The block was surrounded on three sides by large cracks. The fourth side was hollowed out by three people with chalk hammers . Wider notches were dug with these same hammers and antler picks, in the faults to drive wooden wedges into them. The wooden corners were wetted to make them swell in volume and the slab came off after an hour of work. It was then lifted with wooden levers to be able to slide wooden rolls of about 10 cm in diameter intended to move it .
The second experiment aimed to test a transport system for a monumental slab of the type found in tumulus F2. Faced with the impossibility of having a natural slab of this type, a concrete copy of the slab of tumulus F2 was made (identical weight and volume - a single slab 6 m long by 3.50 m wide and 1.30 m high whose weight is estimated at 32 tons). A removable transport path was built with unbarked wooden rollers 40 cm in diameter. The ropes were made from viburnum and ivy fibers by a craftsman according to a tradition still in force on local farms at the beginning of the 20th century . The block, covered with a braided rope net, rested on the wooden rollers arranged perpendicular to the two rails of the raceway. On July 28, 1979, 230 people pulling on ropes and 20 others pushing the block managed to move it 40 m away. Raising the block to 0.50m in height with three levers was then successfully tested.
Experimental archaeology: equipment used
Liberliger, CC BY-SA 4.0, via Wikimedia Commons - Click to enlarge
1997 experiment
In 1997, F. Collin and B. Poisonnier experimented on site with a new “proto-wheel” type traction system with the 32-tonne test block. In this system, the principle of the removable path is retained but each roller is transformed into a hub after having fitted four recesses at each end. These recesses are intended to receive levers arranged radially to drive the movement of the roller. The experiment made it possible to move the block with only about thirty people while saving most of the ropes and the pullers. However, no mechanism of this kind is attested in the Neolithic period.
1998 experiment
In 1998, B. Poisonnier and R. Joussaume experimented with the construction of a trilith at a height of 1.50 m using levers and wooden wedges.
Bullets and Scratches
Oh, dear. It seems our erratic Doctor is confused. He wonders why I mention the "bullet" shape of Newall's boulder and the supposed glacial striations or striae. I will admit I may well have missed or forgotten much of his blog, so many disquisitions, so little time.
But I didn't think I had misremembered, the bullet shape is declared to be diagnostic and the scratches to be glacial striae only a year ago.
25 July 2023
2 July 2022
Click scans to embiggen
Sunday 23 July 2023
Dr. Whitaker's Sarsen Thesis
Sarsen stone in southern Britain: an archaeological and ethno-historical approach to an ancient industry
Katy A. Whitaker September 2022
ABSTRACT
This thesis is an inter-disciplinary study of human engagement with the silcrete called sarsen stone, found dispersed across parts of south-central and south-eastern England and used prolifically since prehistory...
https://centaur.reading.ac.uk/112469/
Nearly 800 pages of Sarsen goodness - It is a big download but worth it.
Erratic Opinions
It might be thought unkind to remind people of the erroneous opinions that have been published on Newall's Boulder now the full scientific analysis is available and any suggestion it is a glacial erratic dismissed. But I think a sample of them should be archived. We should see them as the grit in the oyster, worthless irritants except when they help pearls to be produced.
Click scans to enlarge. All from https://brian-mountainman.blogspot.com/search?q=+newall
Saturday 22 July 2023
The Erratic that came in from the cold
Newall's Boulder - Salisbury Museum
To cut a long story to its appropriate length:
"A rhyolite boulder collected by R. S. Newall in 1924 from an excavation at Stonehenge has been pivotal to arguments concerning glacial versus human transport of the bluestones to Stonehenge. Initial studies suggested that the boulder came from north Wales, and hence was a probable glacial erratic. New petrographic and geochemical analyses however support it being from Craig Rhos‐y‐Felin in west Wales, the source of much debitage recovered from Stonehenge. Examination of the form and surface features of the boulder provides no evidence for it being erratic. Instead, it is considered to be one more piece of debitage probably derived from a broken‐up monolith."
The full paper is available here:
Lithological description and provenancing of a collection of bluestones from excavations at Stonehenge by William Hawley in 1924 with implications for the human versus ice transport debate of the monument's bluestone megaliths: DOI:10.1002/gea.21971
Richard Bevins Rob Ixer Nick Pearce James Scourse Tim Daw
https://onlinelibrary.wiley.com/share/author/YUUAUVRWBNTZTPSQVBGM?target=10.1002/gea.21971
Hawley's excavation of 1924 possibly with "Newall's Boulder" highlighted.
Click photos to embiggen
The more excitable section of the Glacial Transport true believers thought it showed signs of glacial striations where it had been dragged under the ice from Wales but the marks are just a slickensided surface. The paper: "We note that identical slickensides characterise the bedrock outcrop at Craig Rhos‐y‐Felin where we can see clear evidence of lateral movement between adjacent blocks in the outcrop".
The bullet like shape was even cited as evidence of it being ice transported but luckily Dr Brian John provides a photograph showing an identical boulder still happily lying at the Craig.
To illustrate the point further I have superimposed the "Newall Boulder" from Salisbury Museum on to Dr John's photo:
And for completeness here it is floating in what may have been its original position, the tip of one of the pillars at Craig Rhos‐y‐Felin, showing how its shape is characteristic of the rocks in situ.
It seems unlikely that a broken bit of stone was transported to Stonehenge, though less likely things have happened, so the question is when did the pillar break. I tend to think it was probably when the pillar was being re-erected and it was an accident. Or it might have been deliberate.
It could well have been part of Stone 32d which now only survives as a buried stump.
Do read the complete paper, but the simple message is: the boulder and the samples taken from it show no signs of being glacially transported, it is simply "one more piece of debitage probably derived from a broken‐up monolith".
Thursday 20 July 2023
The Sarsen Stone Route to Stonehenge
I originally published my ideas of the route the sarsen stones were taken along to Stonehenge in Nov 2011
Since then the source of the stones has been mainly refined to the West Wood area and so I have just refined the route.
It is available at the this link:
I also took the opportunity to calculate the slope up on Salisbury Plain, it is 50m rise over 1km, a 1:20 slope.
I would emphasis that I think this line just defines a corridor, I am sure that on the ground sensible deviations to either side would be obvious.
Click to embiggen
Original route: https://drive.google.com/file/d/0B-nKFInptaG5MjQ1NmEwOTQtNTBiNS00ZTVkLTllYTctYjZjODhjZDFiZjRh/view?resourcekey=0-7kaPPkXmbCB8giLOVnU7Zw
Tuesday 4 July 2023
Massive Granite Pre-historic Heads
The Olmec colossal heads are some of the most impressive and enigmatic sculptures of the ancient world.
They were erected between 1200 and 400 BC, during the Preclassic period of Mesoamerican chronology. The earliest heads are believed to have been carved at the site of San Lorenzo, which was the first major Olmec city. The heads were then transported to other Olmec sites, such as La Venta and Tres Zapotes.
They are carved from single boulders of basalt, which can weigh up to 40 tons, and were transported over long distances, sometimes as far as 150 kilometers (93 miles).
The exact method of transportation is unknown, but it is likely that the Olmecs used a combination of methods, including:
- Water transport:The Olmecs lived in a region with many rivers and streams, so it is likely that they used boats and rafts to transport the heads over water.
- Log rollers: When traveling over land, the Olmecs may have used log rollers to help move the heads. This would have required a large number of people to push and pull the heads, but it would have been the most efficient way to move such heavy objects.
- Causeways and ramps:The Olmecs also built causeways and ramps to help facilitate the movement of the heads over land. These structures would have made it easier to move the heads over uneven terrain and to lift them up and over obstacles.
The Olmecs were a highly skilled and organized people, and they must have used a great deal of ingenuity and manpower to transport the colossal heads to their sites. The fact that they were able to do so is a testament to their engineering and organizational skills.
Here are some additional details about the transportation of the Olmec colossal heads:
- The heads were carved from basalt, which is a very hard and dense rock. This made them difficult to carve, but it also made them very durable.
- The heads were all carved in a similar style, with large, almond-shaped eyes, prominent noses, and thin lips. This suggests that they were all created by the same group of people.
- The heads were often placed in groups of two or three, and they were sometimes arranged in lines. This suggests that they may have had some symbolic meaning, such as representing the Olmec rulers or their ancestors.
- The heads were found at several Olmec sites, including San Lorenzo, La Venta, and Tres Zapotes. This suggests that the Olmecs had a widespread and complex culture.
The Olmec colossal heads are a fascinating and mysterious part of the ancient world. Their transportation and placement are still a matter of debate, but they are a testament to the ingenuity and engineering skills of the Olmec people.
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