Meadowcroft Rockshelter in Washington County has been known the world over for 40 years for archeological discoveries that have produced awe, wonder and knowledge.
But the most recent discovery there -- this one by a security guard -- that severe rain July 19 had partially flooded the site, provoked distress, concern and a quick response to repair the damage.
Many scholars believe Meadowcroft is the oldest site of human habitation in North America.
Repair work under way at Meadowcroft historic site
Dr. James Adovasio, who has been the principal investigator for the Meadowcroft rock shelter for 40 years, describes current work being done to repair water damage to the 16,000-year-old site. (Video by Kelly Tunney; 8/5/2013)
There is symmetry in the fact that the anthropologist leading a seven-member Mercyhurst University team in re-excavating the National Historic Landmark near Avella is James M. Adovasio, director of the school's Archaeological Institute.
Working for the University of Pittsburgh at the time, he led an excavation begun in 1973 that eventually unearthed more than 20,000 artifacts -- bone and stone tools and basket and pottery fragments -- as well as 956,000 animal and 1.4 million plant remains. Radiocarbon dating indicated the site was used 16,000 years ago as a campsite for prehistoric hunters and gatherers given its shelter, proximity to nearby freshwater springs and sources of plants and animals for food.
As work began Thursday, Mr. Adovasio, 69, stood within the massive sandstone rock shelter, taking in the depth and breadth of the site where as a 29-year-old he began an excavation that would stun the scientific world.
"There is some nostalgia being here again, along with a running film in my head. Back then, we thought it was only 3,000 years old, but by the end of the 1973 season we suspected it was deeper and older than we imagined."
Eventually, the excavation unearthed more than 150 metric tons of dirt containing "basically with things like you ate your breakfast with," he recalled.
Over the past 40 years, Mr. Adovasio has continued his archaeological research at Meadowcroft and delivered hundreds of lectures about the historic site, both on-site and in the classroom, but has not undertaken an excavation of this magnitude there since the early 1990s. Working seven-day weeks, the team should complete its work by mid-August, he estimated Thursday, the first day of excavation.
The damage was caused when water gushed into the enclosed site by an unexpected means -- a channel created by the decomposition of a tree root. The flow of water brought with it sediment that covered an area about 4 1/2 feet wide by 6 or 7 feet high.
The damaged area contains roughly 70 to 75 "visitation moments" from Archaic and Early Woodland natives dating from circa 8000 to 1000 B.C. Because the deposits consist of living surfaces that are literally stacked one upon another, the Mercyhurst team will need to employ exceptionally rigorous excavation protocols.
"This is a pretty unique training and research experience," Mr. Adovasio said standing on a high wooden platform as his team worked in various locations below him. "It's highly rewarding but clearly mentally debilitating at the same time.
"We don't expect we'll find anything dramatically new, but we expect to sharpen our understanding of that time frame. It's a great learning experience from a research standpoint and for students, but it's a gift you don't want to get."
About 8 feet below him, Mercyhurst senior Jessica Higley squatted on a rock plane as she slowly scraped sediment with a trowel into a dust bin. She then used a paint brush to move dirt from the surface so she could see more clearly what she had uncovered. And then she began the process again.
As the archeologists get closer to the rock profile as it appeared before the flooding, they will use straight-edge razors so that only the recent strata is removed. "It's ridiculously tedious work," Mr. Adovasio said.
On rocks below Ms. Higley, 2013 graduate Mike Way did the same methodical work. And not far away, senior Jamie Badams lay on his stomach on a boulder with a downward 40-degree slope. Head down, he stretched his arm and a trowel into a crevice to remove sediment.
Annie Marjenin, a graduate student and the processing lab director, smiled as she noticed Mr. Badams' contortions.
"You have to be creative, you have to figure out the best way to get in there and excavate. It can be very uncomfortable physically," she said.
Every now and then Mr. Badams delivered to Ms. Marjenin a plastic bag filled with sediment that resembled dark brown sugar in color and consistency. Her job is to meticulously document everything that takes place at the excavation -- even recording the names and times of arrival of news reporters and photographers.
Meadowcroft Rockshelter and Historic Village, part of the Heinz History Center's museum system, will remain open during the excavation, which is a bonus to visitors, said director David Scofield. Last year, there were 15,000 visitors from 30 states and 12 countries.
"It's very rare to see the work in progress," he said.
Working in archeology is stimulating and exciting, Ms. Marjenin said, but perhaps not to everyone: "The things you end up finding aren't exciting to most people. It's not like Indiana Jones."
Mr. Adovasio agreed it takes a certain breed. "They look pretty normal," he said of his team, "but you have to be a little demented to do this."
"I'm beyond hope," he said, his laughter joining the silent echoes of 16,000 years.
Michael A. Fuoco: email@example.com or 412-2673-1968. First Published August 5, 2013 4:00 AM