Stonehenge’s Strangest Rock Got here from 500 Miles Away

Stonehenge’s Strangest Rock Got here from 500 Miles Away

By Meghan Bartels

One of many large rocks on the mysterious Stonehenge construction in southern England could have been toted in from about 500 miles away—a exceptional feat to perform some 4,500 years in the past.

Known as the “Altar Stone,” this 16-foot-long, six-ton slab of grayish-green sandstone is situated on the coronary heart of the monument’s inside circle. Archaeologists have lengthy assumed that the rock, like different so-called bluestones, was dropped at the location from western Wales. “It’s just been one of those long-standing ideas that nobody’s really tested,” says David Nash, a geographer on the College of Brighton in England, who has analyzed different rocks inside Stonehenge.

However in new analysis printed on August 14 in Nature, scientists examined that assumption and reached a startling conclusion: The Altar Stone appears to have as a substitute come from northeastern Scotland. That’s a lot, a lot farther away from Stonehenge than Wales and in a distinct course besides. Nonetheless, it stays a thriller who introduced the rock to Stonehenge, how they did it and the way lengthy the journey took. Maybe Stonehenge’s builders sought out the rock and sailed it house; maybe inhabitants of Scotland introduced it south by land as they themselves visited the location; or maybe it arrived by completely totally different means, the researchers say.

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To find out the Altar Stone’s origins, scientists analyzed three various kinds of minerals in its sandstone. Sandstone kinds when tiny particles erode off native mountains and mix into sediment that finally will get compressed into rock. These rock particles comprise fragile minerals referred to as apatite and rutile that inform scientists about latest geology, in addition to zircon, an excellent sturdy mineral that may let researchers peer billions of years into the previous.

As a crystal of zircon, apatite or rutile kinds, hint quantities of radioactive uranium get included into its construction. That uranium decays into lead at a identified fee. By measuring the ratio of uranium and lead, scientists can calculate when a grain of rock shaped. Replicating the method for a lot of grains in a slab of rock offers researchers a form of distinctive “fingerprint” of their age.

The brand new evaluation confirmed Altar Stone’s mineral age fingerprint doesn’t match that of stones wherever in southern England or Wales, the place rocks are typically product of a lot youthful minerals. However the Altar Stone’s profile is much like that of a rock formation referred to as the Orcadian Basin, which is uncovered throughout swaths of Scotland and up into the islands off its northeastern coast.

The evaluation wasn’t complete sufficient to find out the place, exactly, the Altar Stone got here from. The researchers hope to deal with that query in future work by accumulating samples from throughout the Orcadian Basin to check with the Stonehenge knowledge and by analyzing further minerals to sharpen the story of every rock.

The brand new analysis is strictly primarily based in geology, and the authors don’t provide any hypotheses for what might need prompted the traditional builders to haul such a big rock over such an extended distance or how they achieved the feat. It could have even merely been a matter of geological appreciation. “Humans have always had a fascination with finding the perfect rock, and maybe the Neolithic Britons were the same,” mentioned Anthony Clarke, a doctoral pupil at Curtin College in Australia and a co-author of the brand new analysis, throughout a latest press convention.

However these theories will certainly come.

“We’ve got the geology story now, so I’m really looking forward to hearing what other colleagues make of the archaeological story,” says Heather Sebire, an archaeologist who wasn’t concerned within the new analysis. Sebire is senior property curator for Stonehenge at English Heritage, which manages the location.

Whereas the research’s researchers say they by no means anticipated to establish the rock as Scottish, Sebire and Nash say they aren’t stunned, given the identified commerce routes on the time for extra moveable artifacts similar to pottery and axes. “It isn’t a huge shock if there’s potentially that level of communication and connectedness,” Nash says. “If people are prepared to move stone from Wales to Stonehenge, then moving them from other parts of the British Isles to Stonehenge isn’t that far-fetched.”

And for Sebire, the discovering suggests Stonehenge has lengthy held the magnetic attraction and iconic standing that burnish the monument right now. “In the modern day, people come from all around the world to come to Stonehenge; it draws people in,” she says. “It gives me the impression that it was the same idea [back then]—that people wanted to come and contribute to the site.”