Archaeologists conducting the first dig at Stonehenge in decades say they have broken through to areas that could reveal the ancient English monument's original purpose.
Based on years of study, the team believes that Stonehenge served as a religious center and a place of healing even before its famous "goal posts" were erected. "A prehistoric 'Lourdes' was set up at Stonehenge," said Geoff Wainwright, president of the Society of Antiquaries and a key proponent of the theory.
The current two-week excavation, funded by the BBC, is aimed at extracting samples from buried sockets where ancient builders placed the earliest stones erected at Stonehenge, known as bluestones. Figuring out more precisely when those stones were brought to the site could help confirm the theory that Stonehenge's builders thought the bluestones had healing powers.
Tim Darvill, a leading Stonehenge scholar at Bournemouth University who is working with Wainwright to lead the excavation, told the BBC that the first week's work went "really well."
"We have broken through to these key features," Darvill said in a report published Wednesday. "It is a slow process, but at the moment everything is going exactly to plan."
Three years ago, Darvill and Wainwright reported that the bluestones were apparently transported to the Salisbury Plain site from the Preseli Mountains in south Wales, 153 miles (250 kilometers) away. Now they want to compare the rock samples found in Wales with bits of bluestone from the sockets at Stonehenge. Organic material from the sockets will undergo radioisotope dating to determine when the bluestones were placed.
"The excavation will date the arrival of the bluestones following their 153-mile journey from Preseli to Salisbury Plain and contribute to our definition of the society which undertook such an ambitious project," Wainwright told The Associated Press during preparations for the dig. "We will be able to say not only why, but when the first stone monument was built."
What the stones mean
Archaeologists believe that Stonehenge originally consisted of a circle of wooden posts and timbers, built in approximately 3100 B.C. They estimate that the first bluestones were put in place about 2600 B.C., while conceding that the date is an approximation at best. The bluestones were removed from their original sockets about 200 years later; nevertheless, the archaeological team hopes to find fragments of stone left behind.
The excavation marks the first opportunity to bring the power of modern scientific archaeology to bear on a problem that has taxed the minds of so many experts since medieval times: Why were the bluestones so important to have warranted bringing them from so far away?
Stonehenge's roughly 6-foot-tall (2-meter-tall) bluestones are so named because they have a bluish-black appearance. They are the smaller stones that make up the monument, sitting alongside sarsen stones that are about twice as tall and were added later. The sarsen stones are arranged in post-and-lintel formations that served to mark the seasons — and most archaeologists agree that Stonehenge was significant as an ancient astronomical observatory as well as a religious site.
The team led by Wainwright and Darvill hope that this month's excavation will help them fix the date of the start of stone construction with better accuracy. Knowing precisely when the stones were moved could help them match up the construction timeline with a culture that revered the bluestones as having healing properties.
Scientists also may learn more about how the stones were transported. Research shows the bluestones, weighing an estimated 5 tons apiece, may have been dragged from the mountains in south Wales to the sea, put on huge rafts and floated up the River Avon.
The team's archaeologists told the BBC that they uncovered a host of artifacts as they peeled back the layers of their 8.2-by-11.5-foot (2.5-by-3.5-meter) trench, including Roman ceramics, ancient stone hammers and a pottery fragment from England's Neolithic Beaker culture.
First excavation since 1964
This month's dig marks the first time ground inside the inner stone circle has been excavated since 1964. The area is revered as a powerful link to England's pagan past — and to this day, Druids mark the seasons at the site. Cabinet approval was required before the work could begin.
Renee Fok, a spokeswoman with English Heritage, said the project was approved only after experts were convinced of its potential value. She said the project represented "the logical next step" after the two professors located the source of the bluestones in Wales.
"It's the culmination of their work, it makes sense to go back to the stone circle and get a date," she said. "We want to strike a balance. We want the best research, but we can't just say go ahead and dig as you like, it's a very fragile area. Even the Druids are happy with this project. We've spoken to them and they don't object."
Even during the excavation, tourists were able to visit Stonehenge and watch live video coverage of the work from special tents at the site. The BBC has been providing daily updates and plans to air a TV program about the project this fall.
This report includes information from The Associated Press and msnbc.com.