Researchers say they’ve tracked down the origins of Stonehenge’s so-called “Altar Stone,” the monolith on the heart of one of many world’s most mysterious monuments.
The aim of the prehistoric construction in southern England has lengthy been an enigma, although scientists have in recent times been capable of decide the place most of its stones got here from: The upright sarsen stones have been traced to the close by Marlborough Downs space in England, whereas the smaller bluestones have their roots in Southwest Wales.
“The Altar Stone was the last odd one out,” says Anthony Clarke, a PhD pupil at Australia’s Curtin College and the lead writer of a brand new research in regards to the stone’s origins printed this week within the journal Nature.
Clarke, who research geochronology (the science of courting the age of rocks), has all the time been fascinated by Stonehenge specifically — he grew up on a farm in southwest Wales, the place a few of its stones are from.
The six-ton Altar Stone itself — which in the present day lies damaged on the bottom, partially lined by two different stones which can be believed to have collapsed onto it — was lengthy thought to have come from South Wales, however analysis printed final yr successfully dominated out that chance.
Clarke related over e mail with Nick Pearce, one of many Aberystwyth College researchers who had labored on that research, and took him up on his provide to ship over some samples of the Altar Stone for evaluation.
That concerned inspecting the age and chemical traits of every of the mineral grains that got here collectively to kind the sandstone, Clarke explains.
“When you take this profile — this fingerprint, in a way — of the rock, we can forensically compare it to potential source areas all over the U.K.,” he says. “And when we did that … it was strikingly similar to Orcadian Basin sedimentary rocks.”
That was stunning, in no small half as a result of Orcadian Basin is in northeast Scotland — over 450 miles away from the location of Stonehenge.
“When we first got the first kind of batch of data, I looked at it and I said, ‘There’s no way that this can be so distinctly Scottish,’” Clarke provides. “So we did more analysis … and time and time again, it was just so distinctly not from southern Britain, and it pointed towards it coming from this Orcadian Basin. It’s just remarkable.”
The stone’s Stone Age journey might be proof of a excessive stage of societal group
The findings counsel that the roughly 12,000-pound, 16-foot lengthy rock by some means traveled tons of of miles from Scotland to England, properly earlier than the invention of the wheel. (Archaeologists suspect it was put in in Stonehenge someday round 2620 B.C. to 2480 B.C.)
As Clarke places it, simply driving from North Scotland to England is a comparatively arduous journey lately.
“Spare a thought for our Neolithic ancestors, where the heavily forested landscape, rivers, bogs and mountains — it would have been formidable, if not impossible,” he provides.
It’s not clear why the stone was taken so distant, or how lengthy the method took. However there are just a few theories as to the way it made the journey.
One is that huge partitions of ice glaciers introduced the stone southwards, however Clarke says ice-sheet reconstructions present they’d have really moved it in the wrong way.
He and the opposite researchers suppose the most probably clarification is that it was dropped at England by boat, particularly since there may be already proof of a Neolithic marine buying and selling community of issues like instruments and cattle. If that’s the case, he says it might level to a “rather advanced and skilled society.”
“Such routing demonstrates a high level of societal organization with intra-Britain transport during the Neolithic period,” reads the workforce’s research.
The six researchers, primarily based in Australia, Wales and England, spent years working collectively just about on the research. They solely met in particular person for the primary time this week — at Stonehenge, after all.
“It was just weird, I guess, when you talk to people through a screen for several years and then you finally meet them and you’re here at this very special place,” Clarke says. “And the fog was rolling over the hills, and it was very quiet and it was cold, and it was quite a surreal experience.”
Whereas the exact particulars of the Altar Stone’s journey could also be misplaced to time, Clarke says, these findings elevate loads of different questions in regards to the period it got here from — a few of which future archaeologists will hopefully be capable to reply.
Within the meantime, Clarke, who’s 26 and ending up his PhD, will probably be setting his sights on the loads of different instruments and stones — whether or not at Stonehenge or past — that also want monitoring down. Relationship geological materials can put a lot of human historical past in perspective, he explains.
“A human lifetime is 100 years. But the Altar Stone has sat there for thousands of years, the grains within the Altar Stone have sat there for several orders of magnitude more, 3,000 million years,” he provides. “It’s just this idea of time and adding page numbers to Earth’s history.”