Geological Study Proposes Ancient Lake Spillover Carved Grand Canyon 6.6 Million Years Ago

On April 16, a study published in Science provides support for the 'lake spillover' theory regarding the formation of the Grand Canyon. Researchers examined 19 sandstone samples from Arizona's Bidahochi Basin, focusing on zircon crystals to determine sediment sources. Their analysis indicates that approximately 6.6 million years ago, the ancestral Colorado River created Lake Bidahochi, which later overflowed through the Kaibab Arch, shaping the river's current course and the canyon itself. Co-author Ryan Crow from the U.S. Geological Survey describes it as 'a simple but powerful explanation.' Lead author John He from UCLA emphasizes the lake's role in fostering a diverse ecosystem. However, some experts, including University of Colorado Boulder geologist Rebecca Flowers and University of New Mexico geologist Karl Karlstrom, express skepticism about certain aspects. The Grand Canyon draws more than four million visitors each year, and previous studies have uncovered soft-bodied fossils dating back 507-502 million years. It's widely accepted that the Colorado River was present in western Colorado 11 million years ago and flowed out of the canyon 5.6 million years ago, with this new research shedding light on the intervening period.