Lake Tahoe has earned a new distinction. Known for its clarity and as the largest freshwater lake in the Sierra Nevada and the largest alpine lake in North America, it is now recognized as the third-oldest freshwater lake on Earth.
Dr. Winnie Kortemeier, a Geosciences Professor at Western Nevada College, made this discovery by using radiometric dating on the lake’s basaltic lava rock, determining its age to be 2.3 million years. It has always been believed the lake was created during the Ice Age, somewhere between, 10,000 to 2.6 million years ago.
“Fortunately, basaltic lava flows interacted with the lake water and sediments when the lava erupted millions of years ago. This allowed us to use radiometric dating to determine the age of Lake Tahoe,” Dr. Kortemeier explained. “I was surprised to find that, compared to other ancient lakes, it’s the third-oldest in the world.”
Dr. Kortemeier will present her findings to the Geological Society of America at its annual meeting in Anaheim on September 23.
Dr. Kortemeier has been researching Lake Tahoe since 2005. A summary of her findings can be viewed here.
