Mineralization theory research and prospecting progress of rare earth deposits in the world

Mineral exploration investment budget of rare earth in the world has continued to grow in recent years, but it is still less than half of the historical peak in 2012. From a regional perspective, most of the rare earth exploration activities are currently occurred in Australia, Africa and Latin America, whose proportion of mineral exploration investment budget of rare earth in the world have reached 42.9%, 23.2%, and 10.1%, respectively. Exploration companies pay more attention to the proportion of magnet-related rare earth elements （praseodymium, neodymium, dysprosium and terbium） oxides （MREO） in the total rare earth oxide （TREO） content. The proportion of MREO varies for each type of rare earth deposit and for different zones in single deposit, but overall, the proportion of MREO is higher for ionic rare earth deposits and lower for carbonatites. Alkaline intrusion, carbonatite, and ionic rare earth deposit have become important types of exploration. At the same time, breakthroughs have been made in skarn-type rare earth deposits. Important discoveries have been made in rare earth exploration in Australia, the United States, Sweden, Brazil, Malawi, Angola, Greenland etc. Tanbreez-Kvanefjeld in Greenland, Kangankunde in Malawi, Gyttorp in Sweden, and Caldeira in Brazil are typical representatives of alkaline intrusion, carbonatite, skarn, and ionic rare earth deposits, respectively. Scientists have discovered that volcanoes formed by the eruption of iron-rich magma may be enriched in large amounts of rare earths. The rare earth element cerium plays an important role in the main reaction processes of copper, gold, silver and uranium mineralization, and can form a mineralization series dominated by rare earths. Although both Tanbreez and Kvanefjeld rare earth deposits are related to the Ilimaussaq alkaline intrusion and spatially distributed at the north and south ends of the complex, the former has a lower uranium content while the latter has a higher, making the later one of the world’s largest uranium deposits. Mineral exploration practice shows that the “three rare” deposits can appear in single deposit at the same time, such as Tanbreez, which provides direction and ideas for prospecting such deposits.