Rare earth elements in Québec, Canada: Main deposit types and their economic potential A.-A. Sappin 1, a and G. Beaudoin 1 1 Département de géologie et de génie géologique, Université Laval, 1065 avenue de la Médecine, Québec, QC, G1V 0A6 a corresponding author: anne-aurelie.sappin.1@ulaval.ca Recommended citation: Sappin, A.-A. and Beaudoin, G., 2015. Rare earth elements in Québec, Canada: Main deposit types and their economic potential. In: Simandl, G.J. and Neetz, M., (Eds.), Symposium on Strategic and Critical Materials Proceedings, November 13-14, 2015, Victoria, British Columbia. British Columbia Ministry of Energy and Mines, British Columbia Geological Survey Paper 2015-3, pp. 265-273. 1. Introduction Rare earth elements (REE) are strategic metals vital to global economic growth because they are used in a wide range of high-technology industries (e.g., energy, transport, and telecommunications; Walters et al., 2011). The world production and reserves are mainly owned by China. In 2008, the Chinese government introduced export quotas on rare metals, which led to a global search for new sources of REE. Québec has substantial REE resources (Simandl et al., 2012), which may contribute to future production. Gosselin et al. (2003) and Boily and Gosselin (2004) inventoried rare metals (REE, Zr, Nb, Ta, Be, and Li) occurrences and deposits in Québec and, based mainly on lithological association, subdivided them into seven types: 1) deposits associated with peraluminous granitic complexes; 2) deposits associated with carbonatite complexes; 3) deposits associated with peralkaline complexes; 4) deposits associated with placers and paleoplacers; 5) iron oxide, Cu, REE, and U deposits; 6) deposits associated with granitic pegmatites, migmatites, and peraluminous to metaluminous granites; and 7) deposits associated with calc-silicate and metasomatized rocks or skarns. Herein we review REE mineralization in the province, adopting a more genetic scheme based on the classification of Walters et al. (2011). The REE occurrences and deposits are subdivided into primary deposits, formed by magmatic and/ or hydrothermal processes, and secondary deposits, formed by sedimentary processes and leaching. Primary deposits are then subdivided into four types: 1) carbonatite complex-associated; 2) peralkaline igneous rock-associated; 3) REE-bearing Iron- Oxide-Copper-Gold (IOCG) deposits; and 4) hyperaluminous/ metaluminous granitic pegmatite-, granite-, and migmatite- associated deposits, and skarns. Secondary deposits are subdivided into two deposit types: 1) placers and paleoplacers and 2) REE-bearing ion-adsorption clays. 2. Definition and characteristics According to the International Union of Pure and Applied Chemistry (IUPAC), the REE comprise of 17 metals with similar chemical properties, including the lanthanides (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu), Sc, and Y. The REE are not rare in the Earth’s crust. They occur in trace amounts in most rocks, some more abundant than others. The relative abundance of REE in the Earth’s crust varies according to two main factors: 1) the predominance of even- numbered chemical elements relative to their odd-numbered neighbours in the solar system, because of the greater stability of their atomic nuclei (Oddo-Harkins effect); and 2) the predominance of light REE (LREE: La to Eu) compared to heavy REE (HREE: Gd to Lu) in the Earth’s crust, since LREE are more incompatible than HREE (Walters et al., 2011). The REE occur in a wide range of mineral species, such as silicates, carbonates, oxides, phosphates, and clays. However, REE contents of these minerals are variable and only a few of them are of economic interest. For a REE-bearing mineral to be economically viable, it should, for example, contain easily extractable metals, form large-tonnage deposits, and have low radioactive and toxic elements content (e.g., Th, U). The REE (except Sc) belong to the list of critical raw materials defined by the European Union in 2010 (European commission, 2010) and updated in 2014 (European commission, 2014). Of the REE included in this category, Eu, Tb, Nd, Pr, and Dy are predominant in the global REE market in terms of demand and value (Lehmann, 2014). 3. World production and reserves China is the largest producer of REE, with 85% of global REE production in 2014 (Gambogi, 2015). Chinese deposits are mostly associated, directly or indirectly, with carbonatites (e.g., Bayan Obo Fe-REE-Nb deposit; Maoniuping REE deposit) and to ion-adsorption clays (e.g., Ganzhou deposits rich in HREE). The United States is the second largest producer of REE, far behind China, with 6% of the world’s REE production in 2014 (Gambogi, 2015). US production comes mainly from the carbonatite-hosted Mountain Pass deposit, which is rich in LREE. In Canada, no REE mine is currently in operation, although several projects have reached advanced stages of exploration and development (e.g., Hoidas Lake, Saskatchewan; Thor Lake, Northwest Territories; Strange Lake, Québec). Global reserves of rare earth oxides are also predominantly Symposium on critical and strategic materials. British Columbia Geological Survey Paper 2015-3 265