Geologists Rewrite Textbooks With New Insights From the Bottom of the Grand Canyon

Editor’s Note: Press releases are provided to Yellow Scene Magazine. In an effort to keep our community informed, we publish some press releases in whole. The following is a statement from Denver Museum of Nature and Science.

With advanced technology and time-tested knowledge, geoscientists offer innovative, updated perspectives on geology’s “Rosetta Stone”

DENVER – Almost every geology student and scientist worldwide has studied Eddie McKee’s early- to mid-20th-century mapping of the Grand Canyon’s sedimentary record—a foundational work still referenced in textbooks and university lectures globally. Now, scientists from across the western United States, including from the Denver Museum of Nature & Science, have retraced the legendary geologist’s steps in the Grand Canyon. This month they released a paper that reexamines McKee’s groundbreaking studies, builds on his work and refines and redefines a textbook example for understanding Earth’s geologic historic record.

“The Grand Canyon can be thought of as a Rosetta Stone for geology and understanding our Earth’s history,” said study author Dr. James Hagadorn, curator of geology at the Denver Museum of Nature & Science. “Because Grand Canyon rocks record global changes in climate and tectonics, our work helps us understand rock layers that were deposited worldwide millions of years ago during the Cambrian period.”

Supported by a National Science Foundation Division of Earth Sciences grant, Dr. Carol Dehler, professor at Utah State University, led the study with the Denver Museum of Nature & Science’s Dr. Hagadorn, and Dr. Frederick Sundberg, Dr. Karl Karlstrom and Dr. Laura Crossey of the University of New Mexico, Dr. Mark Schmitz of Boise State University and Dr. Steve Rowland of the University of Las Vegas. The report, entitled “The Cambrian of the Grand Canyon: Refinement of a Classic Stratigraphic Model,” was published as the cover story of the November 2024 issue of the Geological Society of America’s GSA Today journal.

McKee studied and documented the stratigraphy and sedimentation of Colorado Plateau geology, especially the Grand Canyon’s Cambrian Tonto Group, for more than 50 years throughout the 20th century.

“The Tonto Group holds a treasure trove of sedimentary layers and fossils chronicling the Cambrian Explosion some 500 million years ago, when the first animals with hard shells rapidly proliferated and sea levels rose to envelop continents with emerging marine life,” said Dr. Dehler, professor at Utah State University.

The new study of the Tonto Group’s rock layers could shed light on how the planet’s systems responded to intense heat and other destructive climate conditions.

“From the Tonto Group’s strata, we’re learning about sea-level rise and the effects of catastrophic tropical storms – probably more powerful than today’s devastating hurricanes – during a period of very hot temperatures when the Earth was ice free,” said Dr. Dehler.

Further, advanced tools provided new insights into rock sedimentation speeds and offered clues on how rapidly marine species, such as trilobites and other “bizarre cockroach-looking creatures,” diversified.

“Our findings are a reminder that science is a process,” Hagadorn says. “Our work in the Grand Canyon, one of the world’s most well-known and beloved landscapes, connects people to this science in a very personal way.”