Neolithic Age Ingenuity and Engineering

Neolithic Age Ingenuity and Engineering

"The sarsen stones make up the iconic outer circle and central trilithon [two vertical stones supporting a horizontal stone] horseshoe at Stonehenge. They are enormous."

"How they were moved to the site is still really the subject of speculation."

"It has been really exciting to harness 21st-century science to understand the Neolithic past, and finally answer a question that archeologists have been debating for centuries."

David Nash, geomorphologist, University of Brighton

"The bluestones, we've known, come from mid-west Wales and they were easy to source because there are inclusions and quartz which you can match to the outcrop. The large stones are pretty uniform and just look like a big block, so it's difficult to interrogate them and find where they are from."

"There are no sarsens of this size left in the downs, that's why it's been such a mystery and some people have suggested they come from elsewhere as you get outcrops in other places where you have chalk land, like Devon and Kent."

"The west wood was overlooked because it's under ancient woodland and a lot of sarsens were removed in the 19th century for road stones, particularly in Swindon, but there are still sarsens buried in among the tees. To be able to pinpoint the area that Stonehenge's builders used to source their materials around 2500 BC is a real thrill."

"We can now say, when sourcing the sarsens, the overriding objective was size -- they wanted the biggest, most substantial stones they could find and it made sense to get them from as nearby as possible."

"This is in stark contrast to the source of the bluestones, where something quite different -- a sacred connection to these mountains perhaps -- was at play."

Susan Greaney, historian, archaeologist with a specialization in British prehistory, Cardiff University

Stonehenge

Before there were the monumentally imposing great cathedrals of Europe, there was Stonehenge. An ancient  circle of massive stone formations dominating a landscape, where sun worship as a Druid temple of sorts spoke to an ancient belief in the divine. Humankind seems always to have had a need of faith, faith in an unknown powerful force imagined as a divine intelligence which created all that exists. The sun was the manifestation of that life-giving, life-sustaining source. One of the Egyptian dynasties was also that of sun-worship when Akhenaten reigned and named the sun Aten.

The building of the ancient Pyramids presented a conundrum just as Stonehenge has done; how massive stone blocks could have been moved to particular sites to construct gargantuan edifices of worship and burial in preparation for the afterlife. Stonehenge's megalithic bluestones were known to have been hauled 225 kilometres from Wales' Preseli Mountains to their destination on Salisbury Plain. A laborious effort of both brute strength and engineering; presumably with the use of log rollers to convey the massive stones over a demanding geology.

Sunset at Stonehenge. Photograph: A Pattenden

A mystery appears to have been cleared with the newfound knowledge that the 52 pale-grey sandstone megaliths known as sarsens originated in the West Woods of the Marlborough Downs, a mere 25 kilometres in comparison distance, north of Stonehenge. Not far from the Neolithic monument site at Avebury. It took the combined work of archaeologists from English Heritage and the University of Sheffield to solve this centuries-old conundrum of human effort in a divine mission of devotion overcoming massive physical effort and distance difficulty to achieve the goal.

A core sample that had been drilled during repair work undertaken in the 1950s involving the "Stone 58" had been taken as a memento to the United States, with permission, by a man who had worked for the company involved in the conservation work when the sarsen core sample was extracted and metal rods inserted to stabilize a cracked megalith. The souvenir moved with this man when he emigrated to the U.S. and was eventually returned to Britain to enable research.

When fragments of the sample were analyzed, researchers were able to establish the geochemical fingerprint of the sarsen which it was taken from, which matched sandstone at West Woods. Most of the sarsens weigh about 20 tonnes, with some as heavy as 30 tonnes; the largest is 30 feet in length. It is hazarded that the Preseli stones were selected for ritualistic purposes while the sarsens were chosen for size, according to archeological logic. Moving such 30 tonne stones would have represented an impossibly difficult prospect.

A large sarsen stone at West Woods, the probable source of most of the sarsens used to construct Stonehenge. Photograph: Katy A Whitaker

Advancing the Archaeological Record

"The most exciting finding is the fact that prehistoric people repeatedly, over millennia, spent considerable amounts of time in high altitudes at a residential site and actively, deliberately made use of the available Afro-alpine resources."
"Prehistoric humans at that time were mobile hunter-gatherers, so they never stayed sedentary at a single site, but had a scheduled 'subsistence circuit.'"
"Hunting giant mole-rats is a clever solution, because their meat is highly nutritious, hunting them is physically not demanding, they are abundantly available, they live in a restricted habitat, and they are year-round available."
Götz Ossendorf, archaeologist, University of Cologne, Germany

"At that time, a large part of the Bale Mountains — about 265 square kilometers [100 square miles] was covered by ice."
"Glaciers were flowing from a central ice cap down into the valleys."
"A high mountain area during a glacial period — normally, people escape such conditions. People normally move downward during cold phases."
Alexander Groos, glaciologist, University of Bern, Switzerland, study co-author

The Fincha Habera rock shelter in the Ethiopian Bale Mountains.

Image: Götz Ossendorf

A new discovery published in the journal Science reflects what is held to be the evidence of human occupation in rock shelters at extreme altitudes as long as 47,000 years ago, in the mountains of Ethiopia. A fairly intact rock shelter was investigated and found to contain bones, tools and hearths, located 3,000 metres above sea level. The findings appear to contradict the archaeological view that humans only took to high elevations in desperation, their very last choice of absolute necessity.

Paleoanthropologists have tended to focus attention on the Rift Valley and similar sites located at low elevations. "We were simply the first to go higher", explained archeologist Dr. Ossendorf, lead author of the newly published study. Humans, it has now been established with confidence, established themselves at high altitudes as hunter-gatherers making use of roasted giant mole-rats and glacier-fed streams, producing tools from obsidian.

The rock shelter that the research team investigated appeared to have been occupied for periods of time at least 16,000 years. Extreme altitudes are known to pose existential challenges -- with brutal weather conditions, while extreme altitudes are too harsh to support much vegetation let alone grasslands, and low oxygen levels can be life-threatening. "Our hominid ancestors were born lowlanders", explained Mark Aldenderfer, archaeologist from the University of California, not involved in the study.

While at the present time in Ethiopia, the Andes and Tibet, humans live at high elevations year-round, archaeologists had always assumed these to be places that were presumably the last choice for human settlement. Recent expeditions to mountains and plateaus have been revealing evidence of human occupation, however, dating back tens of thousands of years.

Dr. Ossendorf and colleagues initiated a project in 2015 in the Bale Mountains of southern Ethiopia, travelling over 1,100 kilometres by foot and using pack horses in a search for signs of early human occupation. Overhanging cliffs were searched to determine whether they had ever been used as shelters. Some 331 rock shelters were discovered to have signs of human occupation, but all had been used in recent centuries by livestock herders, complicating site examination for more ancient human remains.

The researchers did discover that because of a low ceiling, one rock shelter had been undisturbed and when the scientists excavated the floor they discovered the presence of hearths, animal bones and tools representing ample evidence that the rock shelter had once been used for human habitation. The site was called Fincha Habera, where carbon from charcoal remaining in the hearths was analyzed to establish the site age, to validate a range from 31,000 to 47,000 years.

From the evidence it was clear that giant mole-rats represented the bulk of the diet available to these cave dwellers in place of plentiful game available in the lowlands. The obsidian tools originated in the highlands where they were produced, a conclusion made obvious by the researchers tracing the presence of an obsidian outcrop at an elevation of over 4,100 metres -- not far from the Fincha Habera rock shelter.

Views of Fincha Habera from outside and from inside.  Image: Götz Ossendorf