October 10, 2012
Hi-Tech Laser Scan Reveals More Secrets Of Stonehenge
Alan McStravick for redOrbit.com - Your Universe Online
For all its history, Stonehenge remains largely a mystery shrouded in conjecture. So what do we know, with certainty, about this ancient structure?
We know that the stones for the structure, believed to have been used as an important religious site by early Britons some 4,000 years ago, were mined and transported from Pont Saeson in Pembrokeshire. The distance they traveled to Stonehenge was more than 240 miles. Though archaeologists know where these 45-ton stones came from, they still don´t know how the original craftsmen were able to make them stand upright.
Pouring over data from a 2011 laser survey commissioned by English Heritage, researchers have made a startling discovery about what they believe the true nature and intent of Stonehenge was. Extensive archaeological analysis of the high-resolution data produced for all the stone surfaces showed not only the care employed by the original craftsmen, but also the deliberate arrangement of the stones and the purpose behind that arrangement.
Clive Ruggles, an archaeologist from Leicester University, said: “This extraordinary new evidence not only confirms the importance of the solstitial alignment at Stonehenge, but also shows unequivocally that the formal approach was always intended to be from the north east, up the Avenue towards the direction of midwinter sunset."
“We see how the utmost care and attention was devoted to ensuring the pristine appearance of Stonehenge for those completing their final approach to the monument at the two times of the year when sunlight shines along the alignment — when those approaching had the midsummer rising sun behind or the midwinter setting sun ahead.”
Adding to the excitement over their findings, Susan Greaney of English Heritage explained: “We didn´t expect the results of a laser scan to be so revealing about the architecture of Stonehenge and its function.”
The laser survey produced 3D scans showing that the stones to the northeast were carefully “pick-dressed” — worked to be smoother and neater than the other columns — creating a more dramatic spectacle from a specific angle. The intended effect of this workmanship was to allow the stones to be most striking on the summer and winter solstices. By contrast, the southwest facing stones were not smoothed at all. Both solstices attract thousands of visitors to Stonehenge each year.
Additionally, the scan and digital imaging allowed for the discovery of 71 Bronze Age axeheads carved into the stones. This finding brings the total number of axeheads at Stonehenge to 115. This new evidence showed these axehead carvings were made in the Early Bronze Age, approximately 1,000 years after the site was built. These carvings were an early style of advertisement for people who could make or trade in metal goods.
“It is wonderful to have discovered so many more, but what is fascinating is that they are carved without regard to the importance of the siting of the stones — almost as if the people who carved them could no longer quite remember the significance of the monument and how it worked,” said Greaney, an historian at English Heritage.
Other features, such as cracks, hollows and lines, previously thought to have been man made were revealed to be natural features of the stones. Greaney pointed out the frustration of some on the team saying: “Disappointing to some, the scan has also ruled out many poorly defined lines and hollows previously thought to be possible prehistoric carvings.” The preservation of tool marks on the stone was what was most surprising to Greaney.
“Some are quite visible, and have long been noted, but the surprise to me was that everywhere we looked, on every surface, even on very weathered faces of stones which have been lying on the ground for centuries, we could see evidence of the stone working. On some you can see where different groups worked on different areas of the same stone — and with varying skills.”
The confluence of technology and antiquity was pointed out by Marcus Abbott, head of geomatics and visualization for ArcHeritage, and Hugo Anderson-Whymark, an Oxford-based expert on ancient worked stone in the new issue of British Archaeology.
In the report of their findings, they note that 850 gigabytes of data that covers hundreds of faces of stones is equivalent to 750 million pages of printed text or, in terms more easily understood to the tech savvy, 200,000 music files.
"Over the months we have recorded and scrutinized every square centimetre (sic) of Stonehenge in unparalleled detail, revealing over 700 areas of stoneworking, rock art, graffiti, damage and restoration."
The data they poured over digitally stripped weathering and surface texture from the stones allowing the revelation of the carving details. They were able to show that stones thought to be insignificant were, at one time, originally far more imposing. Through the erosion, natural breakage or even deliberate quarrying for use in other building projects, the stones came to appear as they do today.
Because of the smaller nature of some stones and the fact that others are missing outright, many have postulated that Stonehenge was an incomplete project of the early Britons. Citing evidence brought to light by their survey, Greany concluded: “I think we can say now that the monument certainly was finished.”
However, in solving one mystery, another mystery has been created.
The location of the stone that was quarried, Greaney continued, remains “a puzzle.”
“At (another stone site) Avebury, you can readily see stone reused in nearby buildings from medieval times on, but Stonehenge is some distance from the nearest village, so it´s much less easy to see where the stone would have been taken — although we have looked far and wide, we have not succeeded in finding evidence of the re-use of the missing stones.”
As we approach another winter solstice — one that is receiving an inordinate amount of attention — there is little doubt that the site at Stonehenge will attract a far larger share of visitors than in previous years, decades and even millennia.