Uploaded August 2026 | Updated September 2026, 12 minutes ago
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Around 1.3 billion years of Earth's history are missing from the Grand Canyon, creating what geologists call the Great Unconformity. For more than 150 years, researchers have debated what happened to those lost layers and where the missing time went.
The Grand Canyon's rock layers are often described as a history book of Earth, with each layer recording a different chapter of our planet's past. But buried within those towering cliffs is a baffling gap in the geologic record.
Learn why the Great Unconformity remains one of geology's greatest mysteries, how researchers are investigating this billion-year cold case, and why evidence of this missing chapter may be found far beyond the Grand Canyon.
#grandcanyon #greatunconformity #geology #science
Written and Narrated by: Jack Knudson
Edited by: Dominic Grose
Additional Media:
Storyblocks
National Park Service
Grand Canyon National Park
Image Courtesy of Rebecca Flowers/University of Colorado Boulder
Image Courtesy of Gabby Alston/Geological Society of America
NPS Telling Time article Fig. 24
Laurie Crossey/University of New Mexico
Trail of Time Companion p. 7
Karl Karlstrom/University of New Mexico
Carl Bowman, NPS Telling Time article Fig. 19
CC-BY-2.0
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Around 1.3 billion years of Earth's history are missing from the Grand Canyon, creating what geologists call the Great Unconformity. For more than 150 years, researchers have debated what happened to those lost layers and where the missing time went.
The Grand Canyon's rock layers are often described as a history book of Earth, with each layer recording a different chapter of our planet's past. But buried within those towering cliffs is a baffling gap in the geologic record.
Learn why the Great Unconformity remains one of geology's greatest mysteries, how researchers are investigating this billion-year cold case, and why evidence of this missing chapter may be found far beyond the Grand Canyon.
#grandcanyon #greatunconformity #geology #science
Written and Narrated by: Jack Knudson
Edited by: Dominic Grose
Additional Media:
Storyblocks
National Park Service
Grand Canyon National Park
Image Courtesy of Rebecca Flowers/University of Colorado Boulder
Image Courtesy of Gabby Alston/Geological Society of America
NPS Telling Time article Fig. 24
Laurie Crossey/University of New Mexico
Trail of Time Companion p. 7
Karl Karlstrom/University of New Mexico
Carl Bowman, NPS Telling Time article Fig. 19
CC-BY-2.0
ABOUT DISCOVER:
Discover is your source for science that matters, makes sense and is a lot of fun, too.
Visit us at: discovermagazine.com
FOLLOW US:
Facebook: facebook.com/DiscoverMag
Twitter: twitter.com/DiscoverMag
Instagram: instagram.com/discover.magazine
STAY CURIOUS!
