By Sid Perkins
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Analyses of trees and other organic material buried in a riverbank near Lake Superior’s northwestern shore shed new light on how much and when the lake level varied soon after the end of the last ice age.
Researchers have long known that the water level in Lake Superior has fluctuated, but pinning down the dates of those variations has been tough, says Matthew Boyd, a paleoecologist at LakeheadUniversity in Thunder Bay, Ontario. Many techniques that scientists have used to try and estimate the age of beaches, dunes, and other features that denote ancient lake levels aren’t accurate, he notes. Now, Boyd and colleague James T. Teller of the University of Manitoba in Winnipeg have unearthed new clues about the lake’s history, they reported Monday in Houston at the annual meeting of the Geological Society of America.