Xanthoria elegans lichen identified as bioindicator for rare earth elements

Chinese scientists have discovered that a specific species of orange-yellow lichen, Xanthoria elegans, can serve as a visual bioindicator for locating rare earth element deposits. The study, published in the journal Economic Geology, suggests that this lichen tends to grow on carbonate rocks rich in rare earth elements.

Researchers surveyed 67 carbonatite rock samples at the Bayan Obo mining site in Inner Mongolia, China. The lichen was found on 57 of these samples, whereas its presence on granite, sandstone, or quartz was less than 1%. Chemical analysis revealed that the total rare earth element content in the lichen samples ranged from 3,500 to 17,000 parts per million (ppm), with concentrations increasing alongside the levels found in the underlying rock.

Professor Li Yang of Peking University and the Chinese Academy of Sciences noted that the lichen's distinct color makes it easy to spot on exposed rock surfaces. This discovery could allow geologists to prioritize sampling areas more efficiently rather than conducting broad, random searches.