By EDWARD HUSAR

Herald-Whig Staff Writer

LIMA, Ill. -- Thousands of years ago, the seed of a mystery was planted when a hulking, furry creature the size of a modern-day elephant keeled over and died along a bluff in the northwest corner of Adams County.

The carcass of this giant mastodon -- a prehistoric species that roamed Illinois until about 11,000 years ago -- eventually disappeared, covered by the erosive forces of nature and the sands of time.

Then one day in 1957, a farmer named Arthur Andrew was walking along the bluff, several miles southeast of Lima near the former bed of Lima Lake, when he spotted something poking from the ground. It appeared to be an extra-large tooth.

Andrew took the tooth home, and the mystery began sprouting.

For 51 years, residents of the Lima Lake area have been hearing about the local mastodon tooth and wondering how old it might be.

That question might be answered soon.

Steve Tieken, a Quincy archeologist who grew up in that part of Adams County, got permission from the tooth's current owner to have the fossil analyzed by scientists with the Illinois State Geological Survey. The tooth was shipped earlier this month to the ISGS lab at the University of Illinois at Urbana-Champaign.

Scientists will use a special radiocarbon dating technique to try to determine the approximate age of the tooth.

This is an exciting development for Tieken. As executive director of the Quincy-based North American Archaeological Institute, he has been working for years to uncover details about the prehistoric cultures that once inhabited the area around Lima Lake, including the site where the mastodon tooth was found.

Dating the tooth will give future generations a better understanding of the region's ancient history and "really open up a window to that time period," he said.

As a native of the Lima Lake area himself, Tieken has always been intrigued by the legendary tooth, which he first heard about as a child.

"This mastodon find was always part of our psyche," he said.

Now, as an archaeologist working in cooperation with the ISGS, Tieken has a chance to help shed some light on the mystery -- and make a little history in the process.

"What we're hoping to get is the first legitimate date for our area of a mastodon find," Tieken said.

He noted that other mastodon teeth and body parts have been found in this region over the years, but none has been scientifically dated -- until now.

Attaching a date to the Lima Lake mastodon will add to the historical knowledge base of Adams County and contribute to the scientific history of Illinois. That's one reason Tieken's archaeological institute agreed to underwrite the cost of the radiocarbon dating.

"It's a privilege for our organization," he said. "While we're a small nonprofit that works off a small budget, we try to get the most bang for our buck and take on projects like this where we're really bridging the gap between scholars and the public at large."

The tooth caused a sensation when it was first uncovered in 1957.

After word spread that a mastodon tooth was found in Adams County, a geologist from the Illinois State Museum in Springfield, Carlton Condit, visited the site and did some excavation. The whereabouts of Condit's notes or anything he found are unknown, Tieken said.

The site was visited again in 1984 by scientists from Western Illinois University and the state museum. Jeff Saunders, a vertebrate paleontologist who is now curator and chairman of geology at the Illinois State Museum, was among the visitors.

Saunders, who has studied mastodons for several decades, confirmed the tooth was the second right lower molar of a mastodon.

"I've held a lot of mastodons in my hand," Saunders said in an interview this month. "This tooth was heavy and well-mineralized, suggesting it was a pretty old specimen."

Also during his visit in 1984, Saunders inspected a foot-long piece of bone that Andrews had found near the tooth. Saunders identified it as part of the spine of a mastodon, specifically from the thoracic vertebrae. The bone likely came from the same animal as the tooth.

Tieken plans to have the bone scientifically dated, as well. He will send it to the ISGS lab once scientists are done with the tooth.

Different types of dating methods will be used for the tooth and bone. The technique to date the tooth will require taking a tiny sample of the enamel and using a chemical process to draw out some of the remaining carbon-14, a radioactive isotope, for analysis. The dating of the bone will require taking a sample of the bone's collagen and drawing the carbon-14 from there.

Each testing system will then use an "accelerator mass spectrometer" to assess the remaining amount of carbon-14.

Since all carbon-14 is reduced by half every 5,730 years, scientists can calculate the approximate age of certain organic items up to about 40,000 or 50,000 years old.

"We want to know how much C-14 is left," said Hong Wang, director of the ISGS's radiocarbon dating lab. "If we know how much C-14 is left in that mastodon tooth, we will know more accurately than any other dating method how old this mastodon is."

However, if the item being tested is older than 40,000 years, most of the carbon-14 probably would have dissipated by now.

Saunders said it's possible the Lima Lake mastodon tooth is old enough to be considered "carbon dead," meaning it would be at least 40,000 years old, but its exact age would be uncertain.

"In other words, they would not be able to get a finite date," he said. Nonetheless, "even that is knowledge" about the Adams County mastodon, he said. "We don't know anything currently."

Tieken said he suspects the tooth is probably on the old side, based on how highly fossilized it is. But the actual age doesn't matter to him.

"I won't be disappointed if it comes back young or really old," he said. "I just want a true date."

He expects to have results in three to six weeks. Then the mystery might finally be over.

-- ehusar@whig.com/221-3378