source：Sci-News.com
A team of researchers from the U.S. Geological Survey has mapped a rare earth element-bearning deposit in the Mountain Pass region of the eastern Mojave Desert.
Rare earth elements (REEs) are a set of 17 chemical elements (atomic numbers 57-71) in the periodic table.
They are essential in modern civilian and military applications, health-care and medical devices, and ‘green’ technologies.
Although REEs have crustal abundances similar to common industrial-grade metals (e.g., chromium, nickel, copper, zinc, tin, and lead), large economically viable REE deposits are uncommon.
Carbonatite ore deposits are the primary source of REEs. The largest-known carbonatite-related REE deposit is in the Bayan Obo region of Inner Mongolia, China, and has produced around 97% of the global output of REEs.
Increased efforts to characterize geologic processes related to REE deposits in the U.S. have focused attention on the Mountain Pass deposit located approximately 60 miles southwest of Las Vegas, Nevada.
In the new study, Dr. Kevin Denton and his colleagues used geophysical and geological techniques to image geologic structures related to REE mineral-bearing rocks at depth.
Their results suggest REE minerals occur along a fault zone or geologic contact near the eastern edge of the Mescal Range.
“Combined geophysical and geologic investigations of the eastern Mojave Desert carbonate terrane provide new insights into the structural framework of the Mountain Pass REE deposit,” the scientists said.
“This geophysical study of the eastern Mojave Desert carbonatite terrane demonstrates the effectiveness of a multi-technique approach to studying the supporting structures that host REE deposits in the Mountain Pass area.”
“Future studies of Mountain Pass would benefit from high-resolution airborne geophysical surveys capable of continuous data gathering over much broader regions to include coverage of rugged and otherwise inaccessible mountain ranges.”
“For example, high-resolution aeromagnetic, gravity gradiometry, lidar (light detection and ranging), and radiometric data would be ideal for evaluating the region in greater detail.”
“In addition, better understanding of faulting, structural analysis, and kinematics associated with 1.4-billion-year-old structures would dramatically improve the overall constraints and insights related to the REE mineralization in the Mojave Desert.”
The findings were published in the journal Geosphere.