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December 1999 | |
 Carnac's megalithic alignments reopen
In 1990 the pressure of visitor numbers threatened to destabilize some of the megalithic monuments at Carnac (Southern Brittany, France), which include thousands of menhirs, dolmens, and tumuli dating from the Middle Neolithic period, around 3000 BC The French Ministry of Culture decided to close the site during conservation work to all but small, specialized, and escorted groups.
Now, with the stabilization of many standing stones complete, visitors have been allowed to wander freely around 40 percent of this important Neolithic site. Work, however, continues on the rest of the area with further efforts to solidify the bases of other menhirs which, on average, are set just 16 inches into the ground, Neolithic builders giving little thought to solid foundations.
As well as financing urgent conservation measures, the $16-million program includes a new visitor center and the purchase of land and houses on the periphery of the main site. Archaeologists argue that the expropriation of about ten houses in the archaeologically sensitive area is important to reunify the scattered monuments. Several residents, however, are resisting the move.
Others, including the pressure group Menhir Libre (Free Menhir), argue that the current scheme is too restrictive. Next year, from April until the fall, visitor numbers will be limited again, with a maximum of 180 people a day. Another part of the site is planned to reopen in three years.
Source: Archaeological Institute of America (1 December, 1999)
Seahenge dated to spring 2050 BC
Researchers using tree ring and radiocarbon methods have dated a Stonehenge-like timber circle, called Seahenge, found in August 1998 poking out of the Norfolk sea. Government agency English Heritage documented the site, removed the timbers from the mud bank they sat on - to save it from the eroding tides that kept it hidden from us for the last 4000 years - and brought them to Flag Fen Laboratory for analysis and preservation.
The excavated ancient monument's large inverted oak tree, discovered with its roots reaching to the sky last year, was felled in April to June of 2050 BC, according to a report published in the scientific journal Nature. The central oak was more than 150 years old when it fell, perhaps as the result of a windstorm. Researchers picked up the traces of honeysuckle ropes used to pull the stump into place. The 55 oak posts that encircled the inverted oak tree were cut down in April to June of the following year, 2049 BC.
Researchers came up with such accurate dates by combining dendochronology, which matches the growth rings in wood to known historical climate data, with radiocarbon data, a measurement of natural carbon isotope decay.
This is the first time these two methods have been joined, the researchers say. Alex Bayliss, lead author of the report and scientific dating coordinator at English Heritage, says the rings show the trees were cut down in early spring. The central tree was felled or died a year ahead of the rest. "Radiocarbon results then told us the monument dated from between 2,200 to 2,000 BC, but we wanted a more precise answer," she says.
Bayliss and her team next used what is known as a Bayesian model, a complex mathematical process devised by a London Presbyterian Reverend, Thomas Bayes (1702-1761). Involving probability calculations and distribution curves, the mathematical model combined the two sets of information, showing that the central tree had died sometime between April and June 2050 BC. The same type of analysis was applied to the data for the surrounding posts.
Toby Fox, general manager of Flag Fen Excavations, where the timber circle is now available for public viewing, agrees with the report findings. "We actually suspected the monument dated back to the Bronze Age because we can still see marks on the trees where a broad-bladed bronze ax was used," says Fox.
Both Bayliss and Fox theorize that Seahenge - dating to the same time period as Stonehenge - was a type of mortuary constructed by pre-Celtic individuals known as the Beaker people. Fox thinks the body of an important individual was laid to rest on top of the central tree, cradled by its roots. "There's an amazing mysticism about this monument. When we reconstructed it after the excavation, everyone felt a peculiar power in its presence," he says. "Frankly, it's a bit spooky."
The dating confirms the authenticity of Seahenge. Some will also regard it as further justification for the decision to remove the circle from the sands where they were found. Although druid groups opposed the operation, subsequent examination of the posts has shown that the exposed wood was deteriorating much faster than anyone had suspected. If Seahenge had been left where it was built, the world would soon have lost what many now regard as the Bronze Age discovery of the decade. The timbers of Seahenge will be returned to Norfolk when a future for the wooden circle has been decided.
Sources: BBC News (1 December, 1999), Discovery News, MSNBC (3 December, 1999)
Miami Circle finally saved
Miami-Dade County recently accepted a loan from the San Francisco-based Trust for Public Land to the tune of $8.7 million to purchase the Miami Circle. The perfect circle of low, carved limestone, about 38 feet in diameter, was uncovered by county archaeologists after six apartment buildings on the site had been demolished, and just before developers were to begin construction on twin residential towers more than 40 stories tall to replace them.
The 8.5% interest rate makes the county's commissioners sweat, but the conservation organization's eleventh-hour offer was too good to pass up. Now the county will pay the full $26.7 million to developer Michael Baumann up front. Miami-Dade will have two years to repay the loan.
Amid questions raised by University of Florida professor Jerald Milanich as to whether the Circle meant merely be a septic tank drain field, the state of Florida has sent archaeologists back in for three weeks' investigation before the deal is clinched; since February, scientists had been barred from the site while the courts debated its fate.
"It is my impression that any lingering doubts as to the authenticity of the Circle feature exist primarily in the political realm" said John Ricisak, an archaeologist with the Miami-Dade County Historic Preservation Division and field director of the Miami Circle Project.
The last round of study, conducted at the end of November, comprised 80 auger tests and some backhoe work. This latest survey turned up middens to the west of the Circle and more cut holes in limestone across the property. Scarp cleaning and profiling previously excavated trenches has revealed bone and shell artifacts, potsherds dating from 500 B.C. to A.D. 1000, and debitage from canoe-making. Excavation of another septic tank is in progress.
Four new radiocarbon dates from within the Circle date to around A.D. 167 and show no modern intrusion. A fifth date, of a shark skeleton found just below the surface, is about 500 years old, "suggesting," the Dade County Historic Preservation Division said in a released statement, "that the ceremonial importance of the Circle continued through the period of Spanish contact."
The site could eventually become a historical park, perhaps with a museum on its west end. The archaeologists would approve.
Sources: Archaeological Institute of America (23 November and 1 December, 1999), Washington Post (1 December, 1999)
Ancient Louisiana mounds intrigue scientists
The Indian mounds deep in the northeast corner of Louisiana (U.S.A.) don't look like much. Until a timber company clear-cut the trees and thickets at Watson Brake in 1981, nobody even realized they had been built to create a greater shape. And it took nearly two decades after that to discover that they are the oldest known grouping of mounds in the Western Hemisphere. They might not have survived without Reca Jones, an amateur archaeologist.
The mounds and their purpose are a mystery, but they have become a touchstone for archaeologists studying the Middle Archaic period, around 6000 BC to 3000 BC. "Many people thought the Middle Archaic was people running around doing hunter-gathering things for 3,000 years," said Mark Barnes, a National Park Service archaeologist. "They were much more sophisticated than we thought."
Jones had known since she was a child that there were old Indian mounds there. Then Willamette Industries Inc., which owned half the site until the Archaeological Conservancy bought it in 1996, cut the trees. Suddenly Jones could see that there were more mounds than she'd realized, with ridges connecting them into a giant egg shape. It was about 300 yards from end to end and 200 yards across.
"I was here almost the whole time Willamette was here, saying, 'Don't get on the mounds! Don't get on the mounds!'" Jones said. Willamette complied.
Then she asked a Harvard archaeologist to map the site with her, but it wasn't until July 1993 that Joe W. Saunders, the state's archaeologist for that region, drilled the first sample. Bit by bit, the evidence added up. The find went public last year, in Science magazine.
Jones' discovery, her years of work to get a professional to excavate it, and her work in the excavation and reconstruction won her the Society of American Archaeologists' Crabtree Award for amateur archaeology.
Scientists have dated the remains to 5,400 years ago. But many questions may never be answered. For one, why were the mounds built?
Some of the oldest Indian mounds seem to be trash heaps covered with dirt. Here, sometimes the builders covered an area where they had lived and worked, camped on the new surface, then covered it over again. But others are just dirt on dirt. And all of the work appears to have begun at about the same time.
About 60 percent of the oval is a natural ridge which once overlooked swamps and a tributary of the Arkansas River. But why build it higher, and why close in the rest? It probably wasn't flood protection; the land already was well above flood level. The oval encloses nearly 22 acres. Subdivisions have been built on less. But there's no sign that anyone lived in most of that space, aside from three small natural rises. "Perhaps we ask the wrong question. Perhaps constructing the mounds was the purpose," Saunders says.
What can be verified? Bones and shells reveal that the mound builders ate lots of fish, mussels and aquatic snails, and some turtles and small animals. The leftovers also indicate that the people came in the spring and left in the fall.
Only a few fragments of human bones have been found. But bones found in other areas indicate that the builders were probably about 5 feet 2 inches tall. The smallest mounds were about chest-high to them, the biggest as tall as two-story buildings. Excavation and reconstruction won't be the end of work here.
The state wants to buy the northern half of the site and establish a state park. The Archaeological Conservancy bought the southern 80 acres from Willamette in 1996, and sold it last year to the state.
The long-term hope is for a series of sites, one for each period - a prehistoric trail through Louisiana.
Sources: Associated Press, Nando Times (5 December, 1999), The Sun Herald (7 December, 1999)
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