recently developed technique that can measure how deeply buried rock strata had been in the past shows parts of the of Grand Canyon must be very ancient, and had been incised to nearly its current depth before the end of the age of dinosaurs.
This completely upended long established geological wisdom taught in every geology textbook that says the Grand Canyon is a young feature, at most a few million years old, that formed as the Colorado river cut into the Colorado plateau when the plateau rose.
This completely upended long established geological wisdom taught in every geology textbook that says the Grand Canyon is a young feature, at most a few million years old, that formed as the Colorado river cut into the Colorado plateau when the plateau rose.