Stonehenge stone has surprising origins suggested in new study

THE Stonehenge Altar Stone in the heart of the ancient monument of southern England, was probably transported over 700 kilometres from what is now north-east Scotland almost 5,000 years ago according to new research.

The findings of a new study, published Wednesday in the journal Nature, overturn a centuries-old idea that the Altar Stone originated in present-day Wales . The Altar Stone, the largest of the stones used to build Stonehenge, is a thick block that weighs 6 tons and stands in the center of the stone circle.

“This stone traveled an incredibly long way — at least 700 km — and this is the longest journey recorded for any stone used in a monument from that period,” study co-author Nick Pearce, a professor in the department of geography and earth sciences at Aberystwyth University in Wales, said in a statement. “The distance traveled is astonishing for the time.”

The research directly addresses one of the many mysteries of Stonehenge and also opens new avenues for understanding the past, including connections between Neolithic peoples who left no written records, the study authors said.

Construction of Stonehenge began in 3000 BC and occurred in several phases, according to researchers, and the Altar Stone is believed to have been placed inside the central horseshoe during the second phase of construction, around 2620 to 2480 BC.

The discovery of the stone’s origin suggests that ancient Britain and its citizens were far more advanced and capable of moving huge stones, possibly by sea, the study authors wrote.

Unraveling ancient secrets

Substantial research has focused on the types of stone used to assemble the iconic circle located in Wiltshire over the years, and previous analysis has shown that “bluestones”, a type of fine-grained sandstone, and silicified sandstone blocks called sarsens were used in the construction of the monument. The landmark sits on the southern edge of Salisbury Plain, which was inhabited around 5,000 to 6,000 years ago.

The sarsens came from the West Woods near Marlborough, located about 25 kilometres away, while some of the bluestones originated in the Preseli Hills area of ​​west Wales and are believed to be the first stones placed there. Researchers have categorised the Altar Stone with the bluestones, but its origins have remained a mystery until now.

“Our discovery of the origin of the Altar Stone highlights a significant level of social coordination during the Neolithic period and helps paint a fascinating picture of prehistoric Britain,” study co-author Chris Kirkland, professor and leader of the Timescales of Mineral Systems Group in the School of Earth and Planetary Sciences at Curtin University in Australia, said in a statement.

“Transporting such a large load overland from Scotland to southern England would have been extremely challenging, indicating a likely maritime transport route along the coast of Britain. This implies long-distance trade networks and a higher level of social organisation than is widely understood to have existed during the Neolithic period in Britain.”

To better understand the origin of the Altar Stone, researchers analyzed the age and chemistry of mineral grains from fragments of the stone itself.

The analysis revealed the presence of grains of zircon, apatite and rutile within the fragments. The zircon was dated to between 1 billion and 2 billion years ago. But the apatite and rutile grains came from the period between 458 million and 470 million years ago.

The team used analysis of the ages of mineral grains to create a “chemical fingerprint” that could be compared with sediments and rocks across Europe, said study lead author Anthony Clarke, a PhD student in the Timescales of Mineral Systems Group within Curtin’s School of Earth and Planetary Sciences.

The closest match was a group of sedimentary rocks known as the Old Red Sandstone found in the Orcadian Basin in north-east Scotland, which differed completely from the stones found in Wales.

“The findings raise fascinating questions, given the technological constraints of the Neolithic era, about how such a large stone was transported over great distances around 2600 BC,” said Clarke.

The discovery was also personal for Clarke, who grew up in the Preseli Hills in Wales, the origin point of some of the stones at Stonehenge.

“I first visited Stonehenge when I was one year old and now, at 25, I have returned from Australia to help make this scientific discovery – you could say I have come full circle with the stone circle,” said Clarke.

But determining that the Altar Stone originated in what is now Scotland raises a host of new questions.

“It is exciting to know that our chemical analysis and dating work has finally solved this great mystery,” study co-author Richard Bevins, honorary professor in the department of geography and earth sciences at Aberystwyth University, said in a statement. “The hunt will continue to determine exactly where in northeastern Scotland the Altar Stone came from.”

Joshua Pollard, a professor of archaeology at the University of Southampton, called the discovery “a great result.” Pollard was not involved in the research.

“The science is good,” Pollard said. “This is the team that has been active in successfully obtaining smaller bluestones from Stonehenge using a pretty sophisticated battery of techniques.”

Moving huge rocks

Today, the Altar Stone lies broken on the ground, with two stones from the collapsed Great Trilithon structure resting on top of it. A trilithon is a pair of upright stones with a horizontal stone on top of them. Stonehenge’s horseshoe shape includes five trilithons, but the Great Trilithon is aligned with the solstice axis, so on the winter solstice, the Sun appears to set between the two stones.

But researchers question whether the Altar Stone ever stood, as well as what purpose it served.

“One possibility is that the stone was a testament to the dead, and so Neolithic people built stone circles as part of their ancestral rituals of respect,” Bevins said.

Pollard referred to the Altar Stone as a kind of “anomaly, lying in what should be the most sacred piece of space within the monument.”

But how exactly did the enormous Altar Stone get to Salisbury Plain?

At the time, Britain was covered in forests and other impassable geographic features that would have made transporting the stone by land incredibly difficult, the study authors said. But a sea route could have allowed for sea transport, Clarke said.

“While it sounds incredible, Stonehenge is an incredible monument in itself,” Pollard said. “It increasingly feels like the stones are drawn from ancestral sources of those who created Stonehenge — it sort of condenses stories of historical lineages into one place.”

There are other examples of animals, items and stones being transported that suggest cargo could have been shipped across the open sea during the Neolithic Period, the authors wrote in the study.

Stone tools quarried elsewhere have been found throughout Britain, Ireland and continental Europe, including a large stone grinding tool found in County Dorset that came from what is now central Normandy.

There is also evidence that shaped sandstone blocks were transported by rivers in Britain and Ireland.

“While the purpose of our new empirical research was not to answer the question of how it got there, there are obvious physical barriers to transport by land, but it is a daunting journey by sea,” said Pearce. “There is no doubt that this Scottish source shows a high level of social organisation in the British Isles during this period. These discoveries will have huge ramifications for understanding communities in Neolithic times, their levels of connectivity and their transport systems.”

Still, the authors agreed that some questions about Stonehenge may never be answered.

“We know why many ancient monuments were built, but the purpose of Stonehenge will always be unknown,” Clarke said. “And so we have to turn to the rocks. It’s an enduring mystery.”