People love a good mystery, and Stonehenge is one of the gifts that keep on giving.
Every time we learn something new, it just gets more confusing. The latest intriguing, if unhelpful, knowledge is that archaeologists have verified the location of the precise quarries from which the slightly smaller Stonehenge megaliths were taken 5,000 years ago: the Preseli Hills in Pembrokeshire, halfway across Britain.
Also, it seems that the bluestones at Stonehenge may have been repurposed from some other site of worship, or whatever the ancients did at Stonehenge. We don’t actually know.
The smaller Stonehenge standing stones are called bluestones because they look sort of blue. These bluestones consist of dolerite (also known as microgabbro) and rhyolite volcanic spew, which can solidify in the form of vertical columns.
These stones were mined specifically at Carn Goedog and Craig Rhos-y-felin in the Welsh hills, 290 kilometers (180 miles) away from Stonehenge in southern England, says the latest study published by a consortium of geologists and archaeologists headed by Mike Parker Pearson and reported in Antiquity on Tuesday.
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“This was the dominant source of Stonehenge’s spotted dolerite, so-called because it has white spots in the igneous blue rock,” said geologist Dr. Richard Bevins of the National Museum Wales. “At least five of Stonehenge’s bluestones, and probably more, came from Carn Goedog,” he added.
The time frame of the quarrying fits what archaeologists have elucidated about the construction of Stonehenge. They have even found evidence suggesting how the stones were quarried.
But now one has to wonder why and how the ancients lugged up to 80 gigantic stones halfway across Britain, crossing some pretty challenging terrain. And now some are also suggesting the stones were first used somewhere else.
The bigger standing stones at Stonehenge were made of sarsen sandstone, which came from the downs “only” 30 kilometers away. This story is about the bluestones.
Stonehenge, the sequel
It was a century ago that a geologist named H.H. Thomas suggested that the Stonehenge bluestones originated from Wales. He also postulated that they were repurposed sacred stones from another circle altogether – at Waun Mawn, which in contrast was only 3 kilometers from where the stones had been mined.
Why would it even occur to anybody that Stonehenge contained repurposed stones?
“There are stone circles in the Preseli Hills and stone circles where the stones are missing, so the idea was perhaps they had been removed,” co-author Dr. Rob Ixer from University College London explains to Haaretz. “Not much attention was paid to this until the new data showed there are a few hundreds of years between the quarrying and the stones arriving at Stonehenge.”
Where were the stones for those hundreds of years? Either sitting somewhere else, or very slowly wending their way across England to Stonehenge, it seems.
By the way, last year Bevins set out to recheck Thomas’ work and concluded that the long-departed geologist had been right in the general area (the hills), though wrong about the specific spots – which are now agreed as being Craig Rhos-y-felin and Carn Goedog.
It bears stressing that moving gigantic rocks weighing tons was not the norm in Neolithic Europe.
“Every other Neolithic monument in Europe was built of megaliths brought from no more than 10 miles away,” stresses Parker Pearson.
We do not know who built Stonehenge, though some work has shown that some human remains found there also originated in Wales. We can say that, like other renowned and mysterious sites such as Turkey’s Göbekli Tepe, Stonehenge wasn’t built in one stage. And like other monolithic sites of no clear purpose, it remains baffling, and the remote origin of these rocks mysterious.
There are Neolithic circles in the Preseli Hills, says Ixer. “Some are made of the same bluestones as Stonehenge – but they are local stones. There is no other British monument that has used stones that are more than a few kilometers away. Stonehenge is unique. The transport of the stones is unique in Britain and most of Europe.”
Cracking off gigantic slabs
In the Middle East, for instance, huge blocks carved out of the bedrock were used to build things from fortifications to temples to the Western Wall in Jerusalem – and, the team points out, obelisks in ancient Egypt. These were generally made from limestone or some other soft rock.
Not so the bluestone megaliths, says the team. These are volcanic rocks that solidified into natural vertical pillars. The Neolithic megalith-masons would, it seems, stick a wedge into the “ready-made joints” between pillars, bang it in and crack off the giant stone. Wooden wedges could possibly have been used too, but like other organic material, they would have rotted away and disappeared over the last five thousand years, leaving no trace.
Other bluestones containing the igneous rock rhyolite originated in the valley below Carn Goedog, identified by Bevins with fellow geologist Ixer.
As is the case in the Levant, evidence aside from the stones themselves is scanty. Ropes rot, wooden mallets do no better, and the only remnants the archaeologists found were made of stone, coarse hammers and wedges - which were oddly soft.
Parker Pearson has a theory why the Neolithics would use soft stone wedges.
“The stone wedges are made of imported mudstone, much softer than the hard dolerite pillars. An engineering colleague has suggested that hammering in a hard wedge could have created stress fractures, causing the thin pillars to crack. Using a soft wedge means that, if anything were to break, it would be the wedge and not the pillar,” he explains.
The stones would have been gingerly lowered down the slope by ropes, but how they got from the bottom of Welsh hills to Stonehenge is another story. The team suggests some ideas, including transport down the valley to the sea, but nothing concrete.
The discovery of the rocks’ origin is not helpful at all in solving another mystery: who built Stonehenge, or why.
Research last week noted that the earliest monoliths in Europe were built in northern France some 7,000 years ago, and postulated that the practice reached England from there. But in fact, monolithic construction had also been known in Asia, going back millennia before that. We just don’t know.
So, in 3000 B.C.E. – a time of immense social upheaval – people felt it worth the investment to move these stones, the biggest of which weigh 25 tons. The bluestones generally weigh up to 4 tons. When these stones were carved, horses hadn’t even been domesticated yet. You try moving a 4-ton rock nearly 300 kilometers with nothing but a goat and stone tools.