Archaeologists may be able to find sites from the sky

CHAMPAIGN, Ill. -- Bob Melia found the ancient burial ground behind the U.S. Army Construction Engineering Research Lab without turning a shovel of dirt.

Which is good, because Melia was looking for the archaeological site from an airplane 1,100 feet up.

It was a test of a system that can use an airborne infrared camera to pick out everything from ancient civilizations to spent munitions to the remains of missing soldiers.

Melia is a contractor for the National Park Service, which thinks the system has potential for doing mass archaeological surveying on the huge amount of property it oversees.

The Army obviously has interest in finding remains of soldiers missing, say, from the Vietnam War. But it also is interested in archaeological sites on its bases. The law requires historical sites to be catalogued at least, and in some cases may prevent any activities on a piece of property.

"They can be show stoppers," said Michael Hargrave, an archaeologist and researcher with the Army lab.

That's why CERL ended up with an ancient burial ground in its back yard.

Dummy site built

CERL researchers built the grave site, the remains of a pioneer settlement and a prehistoric garbage dump and camp fire pit, common archaeological features all. CERL's Controlled Archaeological Test Site, or CATS, was created to test a variety of noninvasive ways to locate and assess possible archaeological and historical sites, from electric current to magnetic waves.

The test site is laced with animal bones, pottery shards, mussel shells, burnt wood, bricks and other materials characteristic of the sites and all precisely mapped. That allows researchers to make a precise assessment of the accuracy of the methods they're testing.

It was CERL's first test of the infrared camera system, which holds particular promise because it can be operated from an airplane.

"It has the ability to scan across such big areas of land very quickly," Hargrave said.

The rig also was flown over land where the University of Illinois may put its new research farms and golf course south of the campus, looking for signs of long-gone farmsteads from the 1840s and 1860s.

Melia, president of Real-Time Thermal Imaging in Kenner, La., said the system works because the disturbed earth and the materials in the sites are cooler in the morning and warmer in the evening than surrounding terrain, giving them a different thermal signature.

That's true even if the site is several hundred, or thousand, years old, he said.

"We've gotten sites from the 1600s," Melia said. "We've done a number of Civil War and 17th-century sites. With the Civil War, we're finding primarily unmarked cemeteries and battlefields."