Fifteen thousand years ago the Bonneville floods, fed from melting glaciers, carved out the Great Salt Lake and washed out everything from the Snake River Plain to the Clearwater Valley.
The enormous surge left in its wake - among other things - the body of a prehistoric mammoth whose skeleton was excavated last summer from a site near Kamiah.University of Idaho anthropology professor Lee Sappington said recent radiocarbon tests date the Kamiah mammoth at about 14,700 years old, far earlier than originally thought.
"That puts us back further than any type of any human artifacts have been dated around here," Sappington said.
Sappington, along with University of Idaho graduate student Tony Plastino, directed a dig last June to recover the Columbian mammoth that had originally been uncovered in the 1950s by Sigurd Grove of Kamiah.
A group of University of Idaho archaeology students worked about three weeks taking the bones from a former gravel pit.
Sappington said some of the bones were sent to Beta Analytic in Florida for radiocarbon testing. The bone that revealed the date was a rib fragment.
Diggers had thought the mammoth probably was deposited at the Kamiah site by the Missoula floods, which were about 11,000 years ago. That is the time period from which Clovis points, some of the earlier human artifacts, have been discovered.
Tests will continue on the Kamiah mammoth to try to determine whether it died at the site or was washed in by the floods.
Nearly all the parts of the mammoths skeleton were recovered, including a jaw, teeth, a tusk, ribs, vertebrae and parts of the legs, hip and pelvis.
After the University of Idaho is finished testing the mammoth it will be returned to the Lewis County Historical Society, which plans to display it at Kamiah.