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The Colorado River disappeared from the geological record for 5 million years: Scientists now know where it went

Phys · · 1087 words · By Holly Ober
Environmental History Geological Discovery Scientific Methodology

Geologists have used detrital zircon geochronology to determine that the ancestral Colorado River flowed into the Bidahochi basin approximately 6.6 million years ago before spilling over into the Grand Canyon. The research, published in Science, suggests this transition allowed the river to become a continental-scale waterway, influencing the region's ecosystem.

open_in_new Read the original article: https://phys.org/news/2026-04-colorado-river-geological-million-years.html

analyticsAnalysis

10%
Propaganda Score
confidence: 95%
Low risk. This article shows minimal use of propaganda techniques.

psychologyDetected Techniques

warning
Loaded Language 70% confidence
Using words with strong emotional connotations to influence an audience.

fact_checkFact-Check Results

10 claims extracted and verified against multiple sources including cross-references, web search, and Wikipedia.

check_circle Corroborated 6
verified Verified By Reference 2
help Insufficient Evidence 1
info Single Source 1
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“A paper published in Science shows that the river flowed into an upstream lake over the course of a few million years, then likely flowed for the first time into the Grand Canyon.”
CORROBORATED
Multiple web sources (UCLA, AS USA, and others) discuss the study regarding the Colorado River's path and the role of Lake Bidahochi, and a Science journal DOI is referenced in the context of this research.
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wikipedia NEUTRAL — Glen Canyon Dam is a concrete arch-gravity dam in the southwestern United States, located on the Colorado River in northern Arizona, near the city of Page. The 710-foot-high (220 m) dam was built by t…
https://en.wikipedia.org/wiki/Glen_Canyon_Dam
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wikipedia NEUTRAL — The Grand Canyon is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is 277 miles (446 km) long, up to 18 miles (29 km) wide and attains a depth of over a …
https://en.wikipedia.org/wiki/Grand_Canyon
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wikipedia NEUTRAL — Glen Canyon is a natural canyon carved by a 169.6-mile (272.9 km) length of the Colorado River, mostly in southeastern and south-central Utah, in the United States. Glen Canyon starts where Narrow Can…
https://en.wikipedia.org/wiki/Glen_Canyon
+ 3 more evidence sources
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“The Colorado River existed in western Colorado 11 million years ago and first exited the Grand Canyon around 5.6 million years ago.”
CORROBORATED
Two independent web sources (UCLA and AS USA) explicitly state that the river existed in western Colorado 11 million years ago and exited the Grand Canyon around 5.6 million years ago.
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wikipedia NEUTRAL — The Colorado River (Spanish: Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and in northern Mexico. The 1,450-mile-long (2,330 km) river, th…
https://en.wikipedia.org/wiki/Colorado_River
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wikipedia NEUTRAL — The Colorado River is an approximately 862-mile-long (1,387 km) river in the U.S. state of Texas. It is the 11th longest river in the United States and the longest river with both its source and its m…
https://en.wikipedia.org/wiki/Colorado_River_(Texas)
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wikipedia NEUTRAL — The Colorado River toad (Incilius alvarius), (previously Bufo alvarius) also known as the Sonoran Desert toad, is a toad species found in northwestern Mexico and the southwestern United States. It is …
https://en.wikipedia.org/wiki/Colorado_River_toad
+ 3 more evidence sources
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“new evidence suggests it pooled just east of the Grand Canyon, in what is now part of the Navajo Nation, before charting a downstream path that ultimately led to the Gulf of California around 5 million years ago.”
CORROBORATED
Web sources (Daily Sabah, Discover Wildlife) describe the river pooling in Lake Bidahochi on Navajo land before eventually flowing to the Gulf of California.
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wikipedia NEUTRAL — Glen Canyon is a natural canyon carved by a 169.6-mile (272.9 km) length of the Colorado River, mostly in southeastern and south-central Utah, in the United States. Glen Canyon starts where Narrow Can…
https://en.wikipedia.org/wiki/Glen_Canyon
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wikipedia NEUTRAL — Glen Canyon Dam is a concrete arch-gravity dam in the southwestern United States, located on the Colorado River in northern Arizona, near the city of Page. The 710-foot-high (220 m) dam was built by t…
https://en.wikipedia.org/wiki/Glen_Canyon_Dam
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wikipedia NEUTRAL — The Grand Canyon is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is 277 miles (446 km) long, up to 18 miles (29 km) wide and attains a depth of over a …
https://en.wikipedia.org/wiki/Grand_Canyon
+ 3 more evidence sources
verified
“the Kaibab Arch, a topographic high point located in northern Arizona and southern Utah.”
VERIFIED BY REFERENCE
Wikipedia and US Forest Service sources confirm the Kaibab Plateau/National Forest as a high point/plateau in northern Arizona.
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wikipedia NEUTRAL — Rainbow Bridge is a natural arch in southern Utah, United States. With a span of 275 feet (84 m), as reported in 1974 by the Bureau of Reclamation, and height of 290 feet (88 m), it is one of the larg…
https://en.wikipedia.org/wiki/Rainbow_Bridge_National_Monume…
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wikipedia NEUTRAL — The Colorado Plateau is a physiographic and desert region of the Intermontane Plateaus, roughly centered on the Four Corners region of the Southwestern United States. This plateau covers an area of 13…
https://en.wikipedia.org/wiki/Colorado_Plateau
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wikipedia NEUTRAL — The Grand Canyon is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is 277 miles (446 km) long, up to 18 miles (29 km) wide and attains a depth of over a …
https://en.wikipedia.org/wiki/Grand_Canyon
+ 3 more evidence sources
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“He, Douglass and Emma Heitmann at the University of Washington met in the field while studying the remnant deposits of Bidahochi Lake, an ancient lake on Navajo Nation land.”
CORROBORATED
Multiple sources (University of Washington/UCLA, Daily Sabah, Wikipedia) confirm that Bidahochi Lake was an ancient lake located on Navajo Nation land and that He, Douglass, and Heitmann studied it.
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wikipedia NEUTRAL — The Pliocene to Late Neogene Bidahochi Formation lies at an elevation of about 6,300 feet (1,920 m) to 6,600 feet (2,012 m) at the southeast of the Colorado Plateau; the deposits are from Hopi Lake (a…
https://en.wikipedia.org/wiki/Bidahochi_Formation
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wikipedia NEUTRAL — Petrified Forest National Park is a national park of the United States in Navajo and Apache counties in northeastern Arizona. Named for its large deposits of petrified wood, the park covers about 346 …
https://en.wikipedia.org/wiki/Petrified_Forest_National_Park
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wikipedia NEUTRAL — The Shape Shifter is a crime novel by American writer Tony Hillerman, the eighteenth in the Joe Leaphorn/Jim Chee Navajo Tribal Police series, first published in 2006. It was a New York Times best-sel…
https://en.wikipedia.org/wiki/The_Shape_Shifter
+ 3 more evidence sources
verified
“Zircons are microscopic crystals that form in cooling magma.”
VERIFIED BY REFERENCE
Wikipedia confirms that zircon is a mineral (crystal) and the provided web search results discuss its properties and origins in magma.
travel_explore
web search NEUTRAL — Zircon (/ ˈzɜːrkɒn, - kən /) [7][8][9] is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium (IV) silicate, and its corresponding …
https://en.wikipedia.org/wiki/Zircon
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web search NEUTRAL — Sep 1, 2025 · Discover the brilliance of zircon gemstones in our ultimate guide. Learn about zircon colors, crystal properties, value, including the most expensive zircon ever sold and why this dazzli…
https://rayshouseofgems.com/zircon-gemstone-guide/
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web search NEUTRAL — Discover zircon gemstones, from their ancient origins to vibrant colors like blue and green. Learn about their properties, healing benefits, and how to choose quality zircons with our expert buying gu…
https://www.gemselect.com/gem-info/zircon/zircon-info.php
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“Geologists have developed a technique called detrital zircon geochronology that uses lasers or ion beams to measure the ratios of uranium and lead isotopes in hundreds of zircons in a sample.”
CORROBORATED
Two independent web sources (Discover Wildlife and another geological report) explicitly describe detrital zircon geochronology as using lasers or ion beams to measure uranium and lead isotopes.
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web search NEUTRAL — Zircon is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium silicate, and its corresponding chemical formula is ZrSiO4.
https://en.wikipedia.org/wiki/Zircon
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web search NEUTRAL — Using a technique known as detrital zircon geochronology that uses lasers or ion beams to measure the ratios of uranium and lead isotopes in hundreds of zircons in a sample, geologists can work out th…
https://www.discoverwildlife.com/environment/colorado-river-…
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web search NEUTRAL — “Detrital zircon geochronology” employs lasers or ion beams to measure the ratios of uranium and lead isotopes in numerous zircons from a sample. This method allows geologists to analyze each zircon t…
https://interestingengineering.com/science/colorado-rivers-m…
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“The results showed that signatures of the sediments deposited about 6.6 million years ago in Lake Bidahochi closely matched those of other Colorado River deposits downstream and upstream, including the Browns Park Formation in northern Utah and Colorado.”
CORROBORATED
Two independent sources (UCLA and AS USA) confirm that sediments from Lake Bidahochi (~6.6 million years ago) match the Browns Park Formation and other Colorado River deposits.
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web search NEUTRAL — The results showed that signatures of the sediments deposited about 6.6 million years ago in Lake Bidahochi closely matched those of other Colorado River deposits downstream and upstream, including th…
https://newsroom.ucla.edu/releases/how-colorado-river-got-to…
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web search NEUTRAL — The results showed that sediments deposited about 6.6 million years ago in Bidahochi Lake closely matched those from Colorado River deposits both upstream and downstream, including the Browns Park For…
https://scitechdaily.com/scientists-solve-mystery-of-where-t…
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web search NEUTRAL — To understand where the sediments in Bidahochi Lake came from, He and colleagues collected samples of sandstones and later searched them for zircons - microscopic crystals that form in cooling magma.
https://www.discoverwildlife.com/environment/colorado-river-…
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“Study of rock layers in the field from this time period showed signs of rippling that indicated a strong river flowed into standing water, and fossils of large fish species characteristic of fast-flowing waters.”
INSUFFICIENT EVIDENCE
No evidence was found in the provided search results regarding specific ripple patterns or fish fossils in the Bidahochi Lake rock layers.
info
“John J. Y. He et al, Late Miocene Colorado River arrival in the Bidahochi basin supports spillover origin of Grand Canyon, Science (2026). DOI: 10.1126/science.adz6826”
SINGLE SOURCE
While the research is discussed in web results, the specific citation details (2026 date and DOI) were not explicitly verified across multiple independent bibliographic databases in the provided evidence, though the content aligns with the reported study.
info Disclaimer: This analysis is generated by AI and should be used as a starting point for critical thinking, not as definitive truth. Claims are verified against publicly available sources. Always consult the original article and additional sources for complete context.