Scientists have unveiled a treasure map of sorts, pinpointing the locations of rare earth deposits hidden beneath the Earth's surface. This groundbreaking research, led by the University of Cambridge's Department of Earth Sciences, has revealed a fascinating connection between these valuable resources and the planet's lithosphere, the rigid outer shell. The study, published in Nature Geoscience, offers a global perspective on the formation of rare earth-rich igneous rocks, shedding light on the crucial role of the lithosphere.
The international team's findings indicate that the thickness of the lithosphere is a key factor in the concentration of rare earth elements. These elements, essential for modern technologies like smartphones and electric vehicles, have long been a subject of scientific inquiry. By analyzing over 9,000 igneous rock samples from around the world, the researchers discovered a strong association between rare earth-enriched rocks and the lithosphere's variations. This connection is particularly intriguing as it suggests that the lithosphere's thickness influences the formation of these valuable rocks.
Dr. Emilie Bowman, the lead author, emphasizes the predictive power of their research. By understanding the relationship between lithospheric thickness and rare earth-rich rocks, scientists can now anticipate the potential locations of these deposits. This knowledge is invaluable for countries seeking to secure domestic supplies of rare earth elements, especially as the demand for clean energy technologies soars.
The study's unique approach lies in its global scale and integration of various scientific disciplines. Previous research often focused on individual deposits or specific regions, but this study delves into the broader picture. By combining chemical data from igneous rocks with detailed seismic imaging of the Earth's interior, the team was able to map the lithosphere's thickness and structure. This innovative method, akin to using sonar to explore the seabed, revealed that the steep edges of the thickest and oldest lithosphere are prime locations for rare earth deposits.
The formation of these deposits is a slow and complex process. Thick lithosphere creates high-pressure and relatively cool conditions in the mantle, limiting the amount of magma that can form deep underground. These pockets of magma, rich in CO2, slowly cool and solidify into igneous rocks. Over time, geological events can partially melt these rocks again, allowing rare earth elements to concentrate and eventually form economically valuable deposits.
Looking ahead, the research team plans to expand their study to include even older rocks, dating back over 200 million years. This ambitious goal is challenging due to the geological disturbances caused by mountain building and continental rifting. However, Professor Sally Gibson, the senior author, expresses optimism about the potential for predicting mineral occurrences. By understanding the systematic behavior of rare earth deposits, scientists can make significant strides in identifying new sources of these critical elements, ensuring a more sustainable future for technology and clean energy.
