Colorado's Appalachian Geological Roots

Dating of zircon grains found in rocks across the nation shows that a major river system whose sediments ended up on the Colorado Plateau started in the northern Appalachians may have stopped off in Michigan, in an era before the Mississippi River system had developed about 1 billion years ago.

When this ended, contibutions of sediment to the Colorado Plateau continued to arrive from the southern Appalachians about 600 million years ago via a major river system to the South of Michigan in North America.

Efforts to pin down the locations of each "Jurassic-era, continent-crossing river" are ongoing.