- Scientists solved how Utah's Green River cut through ancient Uinta Mountains
- The 2,296-foot-deep canyon defies the 13,123-foot mountain height
- Lithospheric dripping caused ground sinking, enabling the river's path
Scientists may have finally solved a very old mystery about one of North America's most important river systems. They now believe they understand how a river managed to cut through a mountain range in Utah that has existed for millions of years. This discovery helps explain why the Green River flows in a way that has confused experts for more than a century, reported Newsweek.
The Green River is the largest tributary of the Colorado River. The river has carved a 2,296-foot-deep canyon through Utah's Uinta Mountains, even though these mountains are approximately 13,123 feet high. Instead of flowing around the mountains, the river carved a path directly through them. This unique path has puzzled geologists for more than 150 years.
Complicating this puzzle is the significant age difference between the mountains and the river's path. The Uinta Mountains are approximately 50 million years old, but the Green River has been flowing along this "upstream" path for less than 8 million years. Scientists from the University of Glasgow, Scotland, studying the area, pointed out this surprising fact.
The Role Of "Lithospheric Dripping"
Researchers believe that a process called lithospheric dripping is responsible for the river's unusual path. This process slowly lowers parts of the Earth's surface over millions of years and then allows them to rise again.
Smith and his team say they have gathered sufficient evidence to prove that lithospheric dripping, still a new concept in geology, lowered the ground enough to allow rivers to connect.
According to their study, a lithospheric drip formed beneath the Uinta Mountains millions of years ago, causing the ground to sink for a period of time, allowing the Green River to flow through it.
At that time, the river slowly cut through the mountain rocks, creating the path it still flows through today. This path includes the famous Canyon of Lodore. This same path later served to connect the Green River to the Colorado River.
What Is Lithospheric Dripping?
Lithospheric drips form when dense, mineral-rich material accumulates in the lower part of the Earth's crust. Over time, this material becomes so heavy that it sinks into the mantle. The mantle is the thick layer of rock between the Earth's crust and core.
As this heavy material moves downward, it can drag the overlying ground down with it and even bury parts of mountains. When this drip breaks off and continues its descent, the mountainous region gradually begins to rise again. This process creates a distinctive raised pattern on the surface where the drip originated.
Based on how far the drip fell and how fast it descended, scientists estimate that it broke off two to five million years ago. This timing also matches earlier studies that suggested that the Green River carved its way through the mountains and joined the Colorado River system during the same period.
Why Is This Discovery Important?
Smith explained that the confluence of the Green and Colorado rivers millions of years ago altered North America's Continental Divide, creating the boundary separating rivers flowing into the Pacific Ocean from those flowing into the Atlantic Ocean. This also altered the boundaries of wildlife habitats, influencing the evolution of various species. He said this area is crucial to understanding the continent's history.
Smith also said he hopes this new research strengthens evidence that lithospheric drip may be the underlying cause of many more tectonic mysteries than scientists previously understood.
