Oct. 12, 2012
-- It might look like just an ordinary picture of Stonehenge, but this is how the creators of the prehistoric monument wanted the site to be viewed, according to research using the latest 3D laser scanning technology. The groundbreaking analysis determined that the prehistoric monument was built to show off the solstices. In this view Stonehenge would look best when approaching from the Avenue, its ancient processional way to the north east.
Commissioned by the English Heritage, the laser-scan survey revealed in unprecedented detail the efforts made by prehistoric people at Stonehenge. "The result of the project were beyond all expectations. The investigation identified traces of stone working on virtually every stone," Marcus Abbott, head of geomatics and visualization at ArcHeritage, Hugo Anderson-Whymark, an Oxford-based expert on ancient worked stone, and colleagues wrote in the English Heritage report.
The laser-equipped researchers investigated the entire site. The laser scanner collected data with a resolution of 1 mm across the entire stone circle, and of just 0.5 mm for four stone surfaces of special interest. More than 700 surface features came to light.
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The laser highlighted prehistoric carvings from 4,500 years ago as well as damage made by modern visitors. Along with modern graffiti, this image shows scores of little axe heads and a possible dagger added when the slabs were already 1,000 years old.
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Overall, the laser scanning revealed 71 new Bronze Age axe heads, which bring the number of this type of carvings known at Stonehenge to 115.
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But the most interesting findings came from analysis of the stone surfaces. The study showed that the techniques and amounts of labor used varied from stone to stone. According to the researchers, these variations provide almost definitive proof that it was the intent of Stonehenge's builders to align the monument with the two solstices along a north-east/south-west axis. Indeed, the extremely straight and neat outline of the Great Trilithon, compared with all the other trilithons, shows that Stonehenge creators made deliberate efforts to shape it more carefully due to its special position on the solstice axis, just as they did for other stones that flank this axis.
The laser scanning showed that sides of the stones that flanked the solstice axis were most carefully worked to form very straight and narrow rectangular slots. To make them glisten in the sunlight, some stones had their crusts removed. These stones include two of the north-east facing sarsens in the outer circle, the Great Trilithon in the inner sarsen horseshoe, and an isolated upright stone in the south-west segment of the outer circle. By contrast, the stones in the south-western segment of the circle did not have their crusts removed.
The specially smoothed slabs created a dazzling light effect when the sun rays hit the stones. They would glisten in the dawn light on the longest day of the year and at sunset on the shortest This drawing shows Stonehenge in about 2300 B.C., after the construction of the sarsen outer circle and trilithons. Note the solstice axis.
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Scientists have uncovered a portion of an ancient path that may have led to Stonehenge.
While dismantling a modern road that runs near Stonehenge, the archaeologists uncovered two ditches found to be remnants of an ancient pathway called the avenue. Archaeologists have known of the avenue and suspected it led directly to the monument, but the modern road had cut the delicate pathway in two, obscuring its purpose. The new discovery confirms the avenue's role as an ancient pathway to the site.
"We found the bottoms, the truncated ditches, that belong to the feature known as the avenue, which is the processional leading up to Stonehenge," said archaeologist Heather Sebire, a property curator for English Heritage, which manages Stonehenge.
An exceptionally dry season also revealed the imprints where three stones used to lie in the main stone circle, suggesting the massive stone monument was once a complete circle. (In Photos: A Walk Through Stonehenge)
Removing a road
The purpose of Stonehenge is an enduring mystery. Some have argued it was a massive sound illusion, a symbol of unity or a monument built on a sacred hunting ground.
For years, English Heritage had planned to remove the A344 road that snaked through the area and cut quite close to Stonehenge. Though archaeologists suspected the A344 had cut the avenue almost perpendicularly, they weren't optimistic they would find any traces of the earthwork, because the road is now recessed into the ground below the grass level.
But after workers pulled up the tarmac of the road, archaeologists noticed two parallel ditches that were almost perpendicular to the road. The ditches connected the truncated parts of the avenue. Though the banks of the pathway have long since disappeared, the ditches remained.
The discovery confirms that the avenue, which is about 1 foot (30 centimeters) wide, extended 0.3 miles (0.5 kilometers) straight to the stone monument before snaking onward for about 1.5 miles (2.4 km) to the Avon River in the nearby village of Amesbury.
No one knows exactly what the avenue was used for, but archaeologists have some ideas.
"We think it was a processional way; it was where people processed up into Stonehenge," Sebire told LiveScience.
An unusually dry summer also has revealed the presence of three dry patch marks within the stone circle where massive boulders may have once stood. Dry weather can often reveal archaeological features that have been obscured for centuries.
But those traces can be fleeting, Sebire said.
"They're quite ephemeral. It rained a few weeks ago, and it disappeared," Sebire said.
Archaeologists have yet to conduct thorough excavations but have surveyed and photographed the imprints.
The discovery bolsters the notion that Stonehenge was once a full circle; some archaeologists believe that Stonehenge was never completed.
This article originally appeared on LiveScience.com. More from LiveScience.com:
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