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Local Grand Falls Dunes in the Eyes of Scientific Research

August 9, 2021

Do you know that Grand Falls is not only a tourist attraction, but two kilometers away are the Grand Falls Dunes?  USGS scientists are studying the Grand Falls Dunes not only to benefit the people who live on the land, but also to gain insight to how dunes processes work on other planets.

The Grand Falls Dune Field is located ~70 km northeast of Flagstaff, Arizona, 2 km east of Grand Falls, and just north of the Little Colorado River on the Navajo Nation and is known to have formed only six decades ago. It is located upstream from a large waterfall known as both Grand Falls and Chocolate Falls, a popular tourist attraction. 

Scientists at the USGS Astrogeology Science Center (ASC) use the Grand Falls Dune Field as a Mars analog site because it is a close and easily accessible place where dunes can be studied. “Grand Falls Dune Field is the best basaltic dune field in the southern 48 states,” said Dr. Timothy Titus, Space Scientist at ASC. “It is an active dune field with a large basaltic component, which makes it a great Mars Analog.” 

 

General facts about the sand dunes at Grand Falls:

 

Dunes resemble those on Mars.

In some ways, the Grand Falls dunes resemble those on Mars, and in some ways they differ. See them here, spot the differences, and learn interesting details about what scientists do and consider when working on understanding the physics of sand dunes in a desert. 

 

Dunes can grow.

Below are photographs taken months apart within the same year showing dune growth. The snow-capped mountains in the distance are the San Francisco peaks, which are on the outskirts of Flagstaff, Arizona. 

USGS research on sand dunes at Grand Falls
Pic.1 and Pic. 2.  Grand Falls Dune site in 2010. Notice the dune size difference that occured within a few months. Photo Credit: Rosalyn Hayward, volunteer at USGS ASC.

 

Dunes can grow and migrate.

Dunes form when sand is blown around by the wind and piles up. Where a dune forms depends on the strength of the wind and the direction that the wind blows. This can even be in undesirable places such as in the middle of roadways or over the top of houses. 

USGS research on sand dunes at Grand Falls
Pic. 3. Migrating Sand Dune, March 7, 2019.  Pic. 4. Migrating Sand Dune encroaches on fencing. May 22, 2019.   Photo Credit: Dr. Timothy Titus. (Public domain.)

 

Dunes can be natural hazards.

USGS scientists' studies have shown migrating dunes may sometimes pose a hazard to human health, housing, and transportation routes. In response to the changing environment, USGS scientists share their findings with the region's indigenous peoples, along with potential approaches for reducing the hazards of sand and dust movement. Get the fact sheet here for “Monitoring and Analysis of Sand Dune Movement and Growth on the Navajo Nation, Southwestern United States.” 

ASC provides publicly released data about their studies at Grand Falls.  See it here: 

Grand Falls, Arizona: Dune Field Sand Transport 2013 - 2016 - ScienceBase-Catalog

Grand Falls, Arizona: Dune Field Sand Transport 2017 - 2019 - ScienceBase-Catalog

Acknowledgments.
Fieldwork on the Navajo Nation was conducted under a permit from the Navajo Nation Minerals Department. Any persons wishing to conduct geologic investigations on the Navajo Nation must apply for and receive a permit from the Navajo Nation Minerals Department, P.O. Box 1910, Window Rock, Arizona 86515, telephone # (928) 871-6587.