The importance of post-collisional magmatism for global rare earth element resources

The rare earth elements are critical metals for modern technology, arid are most commonly found in deposits associated with alkaline igneous and carbonatite complexes. Although much research has focused on alkaline-carbonatite magmatism in intraplate settings, in reality many REE deposits occur in post-collisional settings. This review of post-collisional REE deposits demonstrates that they typically show evidence for liquid immiscibility between potassic alkaline magmas and F-, Ba- and REE-rich carbonatitic melts or carbohydrothermal fluids. The carbonate-rich melts/fluids rise through the magmatic system and are emplaced at shallow levels, forming the main REE deposits in such complexes. A detailed understanding of the processes operating in these systems can be used to generate geomodels that will be useful for exploration targeting in post-collisional complexes.