Scientists have long understood that the canyon, which has over four million visitors<\/a> from around the globe each year, formed due to the impact of the river between five or six million years ago<\/a> \u2013 but researchers haven\u2019t been able to agree on exactly what processes occurred and when.<\/p>\n Now, a new study<\/a> suggests that the river may have begun to carve its path after an ancient lake overflowed around 6.6 million years ago, providing fresh evidence for a theory first introduced in the 1930s.<\/p>\n As the river began to drain into the vast Bidahochi basin, the basin filled up and spilled over its barrier \u2013 crossing the steep Kaibab Arch<\/a>, a high point in Arizona and Utah \u2013 into what would become the Grand Canyon, the scientists said. <\/p>\n \u201cIn some ways, you could really think of it as the birth of the Colorado River that we know today,\u201d UCLA geologist John He explained in a statement<\/a>.<\/p>\n \u201cThere are rivers everywhere, but a river that carries water and sediment across the continent connects life throughout the region, and the entire ecosystem probably changed as a result of the arrival of the Colorado River into the basin,\u201d he said.<\/p>\n How did they come to this conclusion? By studying the composition of sandstone collected from the Grand Canyon and the Bidahochi basin.<\/p>\n Both contained similar microscopic grains known as zircon crystals. These crystals form in volcanic magma as it cools and do not degrade much over time, helping scientists gain an accurate understanding of when and how they were created.<\/p>\n \u201cThey\u2019re like little time vaults, and by looking at the age and geochemical signature of zircons, we can tell where a sediment that has been moved by a river originated,\u201d He noted.<\/p>\n Using lasers to determine the chemical elements that made up the zircon crystals in the basin, the researchers found the signature of other sediments known to be traced to the Colorado River. <\/p>\n They compared the zircons they had collected with other zircons from the ancestral Colorado River, finding that the 6.6-million-year-old basin sediments matched Colorado River sediments.<\/p>\n And, the zircons weren\u2019t the only evidence.<\/p>\n Rock layers in the area from the same time period showed signs of rippling, too. That indicated that a strong river had flowed into standing water, signaling that the Colorado River had supplied water and sediment to the basin before it spilled over the river flows through the Grand Canyon.<\/p>\n Of course, many questions remain about exactly what happened.<\/p>\n It remains unclear, for instance, if the basin\u2019s lake led to flooding or erosion over time and the study does not rule out other potential ways the river could have flowed into the canyon.<\/p>\n Not everyone is convinced by the new findings, either.<\/p>\n Karl Karlstrom, a geologist at the University of New Mexico, told Scientific American<\/a> that he\u2019s not convinced the river formed the lake and that if an older canyon had already cut across the Kaibab the river likely wouldn\u2019t pool to the elevations in the study.<\/p>\n \u201cThe key details of [the authors\u2019] proposed lake spillover conclusion remain untested,\u201d he said.<\/p>\n![\"How](\"https:\/\/www.newsbeep.com\/uk\/wp-content\/uploads\/2026\/04\/GettyImages-2201330451.jpeg\")
How the Grand Canyon formed has been a hot topic of debate for decades. Scientists say they\u2019ve found new evidence to support one theory (Getty Images)<\/p>\n![\"The](\"https:\/\/www.newsbeep.com\/uk\/wp-content\/uploads\/2026\/04\/GettyImages-1228190539.jpeg\")
The Grand Canyon only stretches over 277 miles. Whereas, the Colorado River spans over 1,400 miles (AFP via Getty Images)<\/p>\n![\"Just](\"https:\/\/www.newsbeep.com\/uk\/wp-content\/uploads\/2026\/04\/GettyImages-474898258.jpeg\")
Just how the river reached the Grand Canyon is still up for debate, including how high the water from the Bidahochi basin would have to reach to flow into the canyon (AFP via Getty Images)<\/p>\n