NASA, USGS Scientists Uncover Mineral Clues in California's Mojave Desert

A team of geoscientists from NASA and the U.S. Geological Survey (USGS) recently deployed to the Mojave Desert near Barstow, California, to investigate a mineral discovery. Equipped with rock picks and hand lenses, their mission was to ground-truth a “fingerprint” detected by a NASA sensor.

The target mineral was topaz, found on public land. The scientists were not searching for gem-grade treasure, but rather using topaz as an indicator. Its presence can hint at a more valuable deposit of porphyry copper below. Porphyry copper deposits, a primary global source of copper, form when magma and hot water from deep underground chemically transform surrounding rock, often occurring in subduction zones like the North American Cordillera.

These deposits can also contain other critical minerals such as molybdenum and tellurium, which are essential for various industries, from steelmaking to solar panels. Finding these deposits is challenging, and topaz is a key indicator because it forms under similar volcanic conditions. The team's goal in the Mojave was to collect samples for lab analysis and gather further evidence.

The scientists included experts from the USGS and Robert Green of NASA's Jet Propulsion Laboratory (JPL) in Southern California. Green described their work as “geologic CSI,” searching for clues to reconstruct geological events by analyzing weathered rocks.

The discovery was made by the AVIRIS (Airborne Visible Infrared Imaging Spectrometer) sensor, built at JPL. This technology, pioneered in the early 1980s, analyzes reflected sunlight to identify minerals by their unique spectral fingerprints. While space-hardened versions explore distant worlds, the AVIRIS line of sensors advances Earth science from aircraft.

The latest model, AVIRIS-5, recently took to the skies as part of the NASA-USGS Geologic Earth Mapping Experiment (GEMx). Led by the USGS, GEMx aims to identify sources of critical minerals across the American West, including in waste rock from active and legacy mines. Since 2023, GEMx flights have covered over 386,000 square miles (1 million square kilometers) of American soil, including most of California.

Ground-truthing the sensor data often involves challenging fieldwork, such as scrambling over steep terrain to collect samples. While testing has confirmed the topaz discovery, determining the extent of any associated porphyry copper deposit is ongoing.

According to NASA Breaking News, a high-altitude NASA ER-2 aircraft supported the GEMx mineral mapping campaign, with flights taking off from the agency’s Armstrong Flight Research Center in Edwards, California, on March 31, 2026.