It sounds like science fiction, but it’s not.  

It’s a partnership between the U.S. Geological Survey and NASA that is bringing together world-renowned geologic expertise and state-of-the-art data collection.   

The data are an essential piece of the USGS’ Earth Mapping Resources Initiative, which is in part funded by the Bipartisan Infrastructure Law. And USGS scientists are using them to see the Earth’s surface – including minerals on the landscape – in a whole new light.  

Light of Many Wavelengths 

The aircraft, which is flown by specialized pilots, is equipped with high-tech sensors that measure light with wavelengths either too short or too long to see, in addition to what is visible to the human eye. These “hyperspectral” data include ultraviolet, short-wave infrared and thermal infrared light.  

Dr. Bernard Hubbard, a geophysicist and from the USGS Geology, Energy and Minerals Science Center in Reston, Virginia, said hyperspectral data can reveal “spectral fingerprints,” which are patterns of light absorption that can be used to identify specific materials on the Earth’s surface. 

The idea isn’t new. Researchers have used satellite measurements of near-infrared light to monitor changes in vegetation and land cover for decades.  

What is new: the unprecedented quality and scale of data yielded through the partnership between USGS and NASA. Earlier this year, the two organizations completed the largest high-quality hyperspectral survey in the world, surveying more than 180,000 square miles of the Southwest with sensors that make it possible to “see” nuanced differences between materials.  

“There is so much potential for this science and how it could change the way we understand our planet,” said Hubbard. 

Decoding the Data

USGS scientists expect these data to be a powerful asset in understanding the mineral resources of the region, in addition to providing insights into topics as wide ranging as potential energy resources, crop health, landslide hazards, water quality, invasive species growth and even climate change.  

But first, USGS scientists have to decipher the data.  

“When the data come in, they just look like squiggles,” said Dr. Gregg Swayze, an emeritus USGS scientist who worked with hyperspectral data for decades. “A lot of work goes into figuring out what the squiggles mean.”    

Part of the key to making sense of the data resides in a small room in Denver, Colorado, where there are rows of shelves packed with vials and boxes.   

This is the USGS Spectral Library, a focus of Swayze’s career. Since the 1970s, the USGS has used lab equipment to collect the spectral fingerprints of thousands of materials, from minerals to different kinds of vegetation, manmade materials like asphalt, and even liquids like water and oil.  

Swayze explained that the USGS also developed algorithms that compare the fingerprints in the library to the “squiggly” data collected above, finding the best match for each piece of the mapped area.  

Out in the field, USGS geophysicists have also been putting in leg work. This summer, Raymond Kokaly, the lead scientist for the ongoing southwest project, and Todd Hoefen have spent a lot of time outside. After a survey flight, they carry a back-pack mounted version of the same spectrometer used on the aircraft over small swaths of the survey area.  

Kokaly and Hoefen explained that by taking measurements at ground level, they can account for atmospheric absorption and scattering and improve the aircraft measurements.  

“Our fieldwork increases the amount of information we can derive from the data,” said Kokaly, who will lead the effort to interpret the data.  

Swayze said using the fingerprints collected in the Spectral Library and the data collected on the ground to “read” the data of such an enormous survey are helping scientists “find the needles in the haystack.”

“It would probably take over 100 years for geologists on the ground to map this area at the same resolution as we get from the aircraft data,” said Swayze. “These data are letting us efficiently identify areas of interest and then focus our field efforts there to gather more information.” 

A Bonanza of Information 

There are many questions that the decoded data might help answer.  

Hubbard, Kokaly, Hoefen and Swayze believe these data will transform our current understanding of minerals in the Southwest, especially ones used in growing economic markets, like rare earth elements used in high-capacity batteries and microchips. 

The data provided from the survey are such fine resolution that scientists will be able to identify specific locations of minerals on the Earth’s surface that could indicate the presence of an underground deposit.  

The data can also be used to identify materials left behind by historic mining. There is growing interest in reprocessing these mine wastes to recover minerals that are in high demand, while supporting the remediation of mine waste sites that might impact water and soil quality.   

Renewable energy resources like geothermal and hydrogen gas can be associated with specific mineral types that the data might also reveal. 

Another application of hyperspectral data is its use in assessing wildfire risk. Kokaly explained that hyperspectral data can be used to see the distribution of invasive plant species, and to compare how much water is present in vegetation, which can both be factors for wildfire risk.  

Dr. Swayze sees the value of the hyperspectral survey in the Southwest extending far beyond just its borders, however.  

“We are doing a lot of work in the Southwest to figure out the relationships between airborne hyperspectral data, the data we collect on the ground, and the fingerprints in the Spectral Library,” said Swayze. “With hyperspectral data from satellites or other airborne surveys, we can extrapolate these same relationships to anywhere on the Earth’s surface.”  

That, said Swayze, is what makes this moment a bonanza.  

Into the Future 

USGS is continuing to partner with NASA to conduct hyperspectral imaging surveys over the continental semi-arid southwest, advancing coverage from California, Nevada, Utah and Arizona towards the Rocky Mountain front range of Wyoming, Colorado and New Mexico. 

The USGS is also partnering with commercial and academic partners to conduct focused surveys in Arizona and New Mexico that will provide even greater detail over several legacy mine sites in the region.  

Hyperspectral data is just one type of data that Earth MRI is collecting in the region. The initiative is also collecting airborne geophysical data that help scientists understand rocks below the Earth’s surface, and geochemical samples of mine wastes to better understand their chemical makeup and resource potential.  

Dr. Darcy McPhee, the USGS Earth MRI program manager, said that, together, the data represent a “once-in-a-generation” investment that is providing a fuller picture of the nation’s resources. She added that the data will likely form the foundation of future geologists’ and geophysicists’ careers.  

“As far as what the investment means for future scientific discovery, I believe the sky’s the limit,” said McPhee.  

To learn about more projects being conducted through Earth MRI throughout the country, visit the Earth MRI Acquisitions Viewer.