Extinct, millions of years old volcanoes: untapped sources of rare earth elements

Good news! Let the rare earth rush begin!

Remember “Rare earth elements aren’t that rare”

"Scientists have simulated the actions of a volcano to conclude that extinct volcanoes across the globe are likely full of rare earth elements that could help supply the world’s growing demand for these difficult to extract resources. ..."

".... “We have never seen an iron-rich magma erupt from an active volcano, but we know some extinct volcanoes, which are millions of years old, had this enigmatic type of eruption,” ...

... “Our findings suggest that these iron-rich extinct volcanoes across the globe, such as El Laco in Chile, could be studied for the presence of rare earth elements.” ..."

"... The researchers simulated volcanic eruptions in the lab by sourcing rocks similar to those from iron-rich extinct volcanoes. They put these rocks into a pressurised furnace and heated them to extremely high temperatures to melt them and learn more about the minerals inside the rocks.

This is how they discovered the abundance of rare earth elements contained in iron-rich volcanic rocks. ...

China has the biggest deposit of rare earth elements on the planet, while Europe's largest deposit of rare earths is in Sweden. Australia has a world-class deposit at Mount Weld in Western Australia and others near Dubbo and Alice Springs. ..."

From the abstract:

"A surging rare earth element (REE) demand calls for finding new REE resources. Iron oxide-apatite (IOA) deposits have substantial REE potential, but their REE enrichment mechanisms remain uncertain, hindering REE exploration. The dominant process of IOA deposit formation is also hotly debated. Here, we use novel layered piston-cylinder experiments to address these questions. Seventeen magmatic FeP–Si immiscibility experiments, across 800–1150 °C, and at 0.4 and 0.8 GPa, reproduced many natural textural (e.g., dendritic magnetite) and geochemical (e.g., DLFeP–LSiTi/Fe  < 1) features of IOA deposits. Magmatic-hydrothermal fluid bubbles and iron oxide-bubble pairs formed as well. The results strongly support FeP–Si immiscibility as a controlling factor in IOA deposits, although not mutually exclusive with other models. Light REE partition into FeP liquids, preferentially to heavy REE, explaining the light REE enrichment of IOA deposits. Some DLFeP–LSiREE values reach above 100, much higher than previously reported. Hence, any FeP rich rock that experienced magmatic Fe-Si immiscibility (e.g., IOA, nelsonites) is expected to be light REE enriched and should be considered as a REE exploration target."

Extinct volcanoes: untapped sources of rare earth elements

Extinct volcanoes a 'rich' source of rare earth elements, research suggests (original news release)

Silicate and iron phosphate melt immiscibility promotes REE enrichment (open access)

Figure 1 (a) Previous immiscibility experiments doped with trace elements, overlain by our new experiments (triangles, squares, and pentagons).  ... (b) The layered set-up of representative experiments.