Sewer construction workers made an unusual discovery on Des Moines' southeast side in January: remains of a human body archeologists believe could be as old as 7,000 years.
The remains are thought to be from the Middle Archaic period and were found near a site where scientists believe early Iowans harvested, cooked and consumed clams thousands of years ago.
Ancient ash and charcoal remains, apparent signs of a Stone Age clambake, also were uncovered.Studies are ongoing, but it is one of the earliest and best examples of an Archaic site discovered in Iowa. Its exact location is not being revealed because of fears of looters.
"It is a rather unique site, not only in Iowa but in the Midwest," said state archaeologist John Doershuk. "The site overall, if you take all of its aspects, is definitely one of the earliest that's been excavated in Iowa."
There likely will be national interest, said Ben Thomas, director of programs for the Archaeological Institute of America.
"On a national level, we are still struggling to understand the first people of the Americas," Thomas said. "Any information like this is hugely beneficial to filling in the gaps."
While archaeologists are thrilled at the prospects of learning more about Iowa's ancient past, some people are concerned about the consequences of the discovery.
The find will delay the original $37.8 million sewer project for at least six months and cost the Des Moines area's Wastewater Reclamation Authority an estimated $1.5 million or more because of delays caused by the archaeological dig.
Perhaps worse is that the massive construction project may miss a Dec. 31, 2013, deadline under an agreement with state and federal officials. An extension likely will be requested but the wastewater authority and its customers could face tens of thousands of dollars in fines.
"It's fascinating if it's your backyard. It's not fascinating if it's on your construction site," said Des Moines Public Works Director Bill Stowe.
Doershuk and Thomas said archaeologists are sensitive to costs but note there is a federal and state obligation to preserve ancient artifacts.
Iowa must abide by the 1966 National Historic Preservation Act that requires projects using federal money to evaluate the impact a project may have on archaeological or historic sites. Artifacts that are found will be placed in a repository with the state archaeologist and likely will be displayed for the public after work is completed.
"Those kinds of costs and overruns do happen," Thomas said. "It's not uncommon, but of course the people involved in development and actual construction hate to see it."
Archaic-period materials have been found across the state, including such artifacts as projectile points more commonly known as arrowheads. But, until the Des Moines site was discovered, few other Iowa archaeological digs have compared in age, complexity and scope, Doershuk said.
The closest comparison is a site in Cherokee County unearthed in the 1970s. That site included a number of tools as well as a whistle made of bird bone that is believed to be the earliest artifact of its kind in North America.
The most common ancient artifacts associated with humans are 1,000 to 3,000 years old, including many of the burial mounds across the state.
James Enloe, a professor of anthropology at the University of Iowa, taught some of the archaeologists leading the Des Moines excavation and is aware of the find.
Other material found at the site includes what appears to be flooring from dwellings that would be about 7,000 years old. Enloe said such a find is exciting because it challenges assumptions that humans from that period were nomadic and rarely stayed long in any place.
"Investing in houses is a longer-term occupation and tells us a little more about how early people adapted to Iowa," Enloe said.
Ancient human remains - those 150 years or older - are protected under Iowa law. The state archaeologist typically works to preserve burial sites. When that's not possible, the body is examined and buried in a state cemetery that is closed to the public.
"This is the kind of thing that the process was set up for," Doershuk said of the state's preservation work with the Des Moines project. "It was set up to make sure that projects that are important to society proceed but don't erase history."
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