District Digs into History; Archaeologists Uncover Relics Dating to 9000 B.C

Article excerpt

Byline: Gabriella Boston, THE WASHINGTON TIMES

Washington and the region surrounding it has been a hub of power and politics for hundreds of years. Think George Washington, Thomas Jefferson and George Mason, to name a few - but that's hardly going back far enough.

American Indian findings in and around the District indicate that the region was home to wealthy chiefs for thousands of years, archaeologists say. They have found evidence that humans have been in the area since at least 9000 B.C.

How do they know that the evidence, such as a projectile point, which looks like an arrowhead (a later invention), is 10,000 years old as opposed to, say, 5,000 years old?

Archaeologists use several methods to identify and date objects they find. With artifacts from the prehistoric period - up to the 1500s, when Europeans came to this continent and started writing down their observations - one of the methods they use is radiocarbon dating, which was developed during World War II.

In radiocarbon dating, the breakdown of carbon isotopes in organic matter is measured. All plants and animals ingest carbon dioxide throughout their lives. When the plants and animals die, the radioactive carbon isotopes start breaking down.

The half-life of Carbon 14, the isotope measured, is 5,730 years. That means if half of the isotope remains in the organic matter, the object studied is 5,730 years old.

Over the years, the method has been refined, and now just a milligram of organic material is needed to date an object. A couple of decades ago, archaeologists needed about 8 grams for the same analysis.

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The District and surrounding areas are littered with prehistoric sites where radiocarbon dating has been used to identify and date artifacts.

Inside the District, Indian sites have been found just north of the Kennedy Center, in Rock Creek Park and on American University's campus, to name just a few places.

"We have found 6,000-year-old projectile points right here on campus. I think it was at the Mary Graydon Building," says Joe Dent, a professor of anthropology with a specialty in archaeology at American University.

Indians probably were attracted to the area because of the easy access to the Potomac River and to the Chesapeake Bay, which were important for both fishing and transportation.

"It's as real estate agents today would say, 'It's all about location, location, location, '" says Stephen Potter, regional archaeologist for the National Capital Region of the National Park Service. He has three archaeologists under his supervision.

Every year there are about 50 archaeological projects in the District and surrounding areas. The projects are led by schools, such as American University and Mr. Dent; the National Park Service, which oversees digs in national parks; and local governmental groups, such as Alexandria Archaeology and the District Office of Historic Preservation.

Every time someone wants to build on federal land or use federal money, an archaeological study is commissioned to see if anything historically significant may be on the property, Mr. Dent says.

The most significant findings during the Metrorail excavations were Indian artifacts that were between 2,000 and 10,000 years old at the site of what is now the Greenbelt storage facility, he says.

Mr. Potter says he has seen his share of projectile points and pottery in his more than two decades as the lead archaeologist for the National Park Service in the region, but he's still excited about each new dig because it might tell him something he doesn't know.

"It is only through archaeology that we will find out about life here in prehistoric times," he says. "There is no written documentation."

During what he calls one of his most exciting projects, just north of the Kennedy Center - the Ramp 3 excavation - archaeologists discovered a burial site that was determined through radiocarbon dating to be about 1,300 years old. …