Tuesday March 9 2:56 PM ET

Tests: Miami Circle Site At Least 2,000 Years Old

By Jim Lonny

MIAMI (Reuters) - Scientific tests on charcoal found in the mysterious Miami Circle, a dusty Indian relic at the heart of a fierce political battle, suggest the site was occupied by humans at least 2,000 years ago, archeologists said Tuesday.

The tests were the first done on artifacts found at the site and the first scientific indicator of the age of the nondescript 38-foot circle. It was found last summer on a downtown plot of land where a developer wants to erect a $100 million condominium.

A series of man-made basins and holes hacked into the limestone bedrock on one of Miami's priciest parcels of real estate at the mouth of the Miami River, the Miami Circle has become the focus of a war between city and county governments, and developers and preservationists.

Native-American groups have adopted the circle as an illustration of America's ill treatment of sacred Indian sites. The circle is believed to be the foundation of a ceremonial lodge constructed by indigenous Tequesta Indians before they vanished in the decades after European occupation of Florida.

The Miami-Dade County Commission on Feb. 18 voted to attempt to buy the 2.3-acre (0.92-hectare) parcel of land and obtained a court order preventing construction at the site. The court order came over bitter opposition from the city of Miami, which stands to lose millions of dollars in tax revenue if the condominium is not built.

The Florida cabinet, made up of the governor and other executive branch leaders, was considering Tuesday a proposal to use state money to help buy the land.

Carbon-dating tests were completed on two small bits of charcoal, probably created by Tequesta fires, said John Ricisak, a Miami-Dade County historic preservation specialist.

The tests showed that a sample found in one of the basins that form the circle was 1,800 to 2,100 years old, Ricisak said. A charcoal sample found in the earth that covered the circle was 1,850 to 1,990 years old.

``It tells us that the occupation of the site...goes back probably 2,000 years,'' Ricisak said. ``It does not come anywhere near proving that the circle itself may also be that old.''

Experts had previously said the circle could be 500 to 800 years old.

Carbon dating measures the amount of carbon 14, a slightly radioactive isotope of carbon found in all organic matter, remaining in ancient material. It enables scientists to determine the age of fossils and other artifacts by comparing the test results to an international standard.

Ricisak said testing was to be done on other Circle artifacts, including bone, shell and the skeleton of a shark. But it was unclear whether it would be possible to test the limestone bedrock into which the formation is carved.

Scientists also were trying to determine the origin of two basalt ax heads found at the site.

Basalt is a rock of volcanic origin that does not occur naturally in Florida. The two nearest possible sources are the Appalachian Mountains of eastern North America and the highlands of Guatemala, scientists said.