Treasure hunting
The optical techniques used at the Microdevices Laboratory have advanced continuously since the first AVIRIS instrument took flight in 1986. Four generations of these sensors have now hit the skies, analyzing erupting volcanoes, diseased crops, ground zero debris in New York City, and wildfires in Alabama, among many other deployments. The latest model, AVIRIS-5, features spatial resolution that’s twice as fine as that of its predecessor and can resolve areas ranging from less than a foot (30 centimeters) to about 30 feet (10 meters).
So far this year, it has logged more than 200 hours of high-altitude flights over Nevada, California, and other Western states as part of a project called GEMx (Geological Earth Mapping Experiment). The flights are conducted using NASA’s ER-2 aircraft, operated out of the agency’s Armstrong Flight Research Center in Edwards, California. The effort is the airborne component of a larger USGS initiative, called Earth Mapping Resources Initiative (Earth MRI), to modernize mapping of the nation’s surface and subsurface.
The NASA and USGS team has, since 2023, gathered data over more than 366,000 square miles (950,000 square kilometers) of the American West, where dry, treeless expanses are well suited to mineral spectroscopy.
An exciting early finding is a lithium-bearing clay called hectorite, identified in the tailings of an abandoned mine in California, among other locations. Lithium is one of about 50 minerals at risk of supply chain disruption that USGS has deemed critical to national security and the economy.
Helping communities capture new value from old and abandoned prospects is one of the long-term aspirations of GEMx, said Dana Chadwick, an Earth system scientist at NASA JPL. So is identifying sources of acid mine drainage, which can occur when waste rocks weather and leach into the environment.
“The breadth of different questions you can take on with this technology is really exciting, from land management to snowpack water resources to wildfire risk,” Chadwick said. “Critical minerals are just the beginning for AVIRIS-5.”
More about GEMx
The GEMx research project is expected to last four years and is funded by the USGS Earth MRI, through investments from the Bipartisan Infrastructure Law. The initiative will capitalize on both the technology developed by NASA for spectroscopic imaging, as well as the expertise in analyzing the datasets and extracting critical mineral information from them.
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