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| The stone circle of Stonehenge is silhouetted at sunrise during the pagan festival, Summer Solstice, in Avebury, Wiltshire, 21 June 2007 (AFP Photo/CARL DE SOUZA) |
Washington (AFP) - Stonehenge, a Neolithic wonder in
southern England, has vexed historians and archaeologists for centuries with
its many mysteries: How was it built? What purpose did it serve? Where did its
towering sandstone boulders come from?
That last question may finally have an answer after a
study published Wednesday found that most of the giant stones -- known as
sarsens -- seem to share a common origin 25 kilometers (16 miles) away in West
Woods, an area that teemed with prehistoric activity.
The finding boosts the theory that the megaliths were
brought to Stonehenge about the same time: around 2,500 BCE, the monument's
second phase of construction, which in turn could be a sign its builders were
from a highly organized society.
It also contradicts a previous suggestion that one
large sarsen, the Heel Stone, came from the immediate vicinity of the site and
was erected before the others.
The new paper appeared in the journal Science
Advances.
Lead author David Nash, a professor of physical
geography at the University of Brighton, told AFP the technology required to
analyze the sarsens, that stand up to nine meters tall (30 feet) and weigh as
much as 30 metric tons, did not exist until recently.
He and his team first used portable x-rays to analyze
the chemical composition of the rocks, which are 99 percent silica but contain
traces of several other elements.
"That showed us that most of the stones have a
common chemistry, which led us to identify that we're looking for one main
source here," said Nash.
Next, they examined two core samples from one of the
stones that were obtained during restoration work in 1958 but which then went
missing until resurfacing in 2018 and 2019, respectively.
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Graphic on a new study that aims to track the origins
of some of the largest
stones at Britain's ancient Stonehenge monument. (AFP Photo/John SAEKI)
|
They performed a more sophisticated analysis technique
called mass spectrometry on these samples, which detects a bigger range of
elements at a higher precision.
The resulting signature was then compared to 20
possible source sites for these sedimentary rocks, with West Woods, Wiltshire
found to be the closest match.
'Enormous endeavor'
Previous work has found that Stonehenge's smaller
"bluestones" came from Wales, about 200 kilometers (160 miles) to the
west, and the new study says that they and the sarsens were placed at the same
time.
"So it must have been an enormous endeavor going
on at that time," said Nash. "Stonehenge is like a convergence of
materials being brought in from different places."
Just how the early Britons were able to transport the
boulders weighing up to 30 tons a distance of 25 kilometers remains unknown --
though the prevailing idea is they were dragged along sleds. The site's
significance also remains mysterious.
"I think you're looking at a very organized
society there," added Nash.
As for why they picked West Woods, he said, it could
have been a case of pragmatism as it was one of the closest sites.
But the area was also a hive of Early Neolithic
activity, and is home to numerous ancient burial sites known as a barrows, a
large circular earthwork and a polissoir -- a rock used to sharpen ancient
stone axes.
Nash said that the method the research team had
devised could help answer further archaeological questions, such as the route
used to transport the boulders -- which can be inferred if sarsen chippings are
discovered at waypoints.
He and his team also hope to use the techniques on
other ancient sarsen sites scattered around Britain.
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