Institute of Geology, Karelian Research Center, Russian Academy of Sciences, Petrozavodsk, Russia:

L. V. Kuleshevich, Leading Researcher, Candidate of Geologo-Mineralogical Sciences, kuleshev@krc.karelia.ru
A. V. Dmitrieva, Researcher, Candidate of Geologo-Mineralogical Sciences

Rare earth elements (REE) have recently found wide application in different branches of industry and in new technologies. In Karelia REE occur in alkaline rocks, carbonanites, lamproites, high and moderate alkalinity garnets, pergamites, alkaline and associated metasomatites, quartz conglomerates (paleoplacers) as well as in some uranium and noble metal mineralizations, REE exist in various minerals–bastnasite, parasite, monazite, xenotime, loparite, etc. none of commercial-scale ore objects have yet been found in Karelia. For this reason, this study aimed to assess alkaline and moderately alkaline rocks, associated metasomatites, as well as conventional and some unconventional types of ore mineralization in terms of REE occurrence. REE and their minerals were determined by ICP–MS and microprobe analyses. Assaying embraced different-age alkaline and moderately alkaline rock masses and systems, such as Elisenvaar, Tiksheozero–Eletozerom Salminsko-Ulyaleg, Syargozero, Kostomuksha intrusions (Shurlovaar massif, lamproites, garnet massifs), rocks of Koikar and Kumsa sills, skarn alkaline metasomatite (albitite), greisens, Cu–S and Cu–Au–Pt–Se–U mineralization of albitite and associated iron–magnesian metasomatites (related with IOCG-type). Concentrations of REE and associated rare elements, as well as the minerals ensuring these concentrations are determined. These research findings should facilitate discovery of REE-promising mineralizations and their predictive appraisal in the territory of Karelia.
The studies were carried out by R&D program of the Institute of Geology, Karelian Research Center, Russian Academy of Sciences.

1. Humphries M. Rare Earth Elements: The Global Supply Chain : CRS Report for Congress. 2013. Available at: https://fas.org/sgp/crs/natsec/R41347.pdf (accessed: 09.10.2018).
2. Gasanov A. A., Yurasova O. V., Kharlamova T. A., Alaferdov A. F. Electrolyzer design for cerium oxidation. Tsvetnye Metally. 2015. No. 8. pp. 50–54. DOI: 10.17580/tsm.2015.08.06
3. Avdonin V. V., Boitsov V. E., Grigoriev V. M., Seminskii Zh. V., Solodov N. A., Starostin V. I. Metalliferrous deposits. 2nd enlarged and revised edition. Moscow : Akademicheskii prospect, 2005. 720 p.
4. Usova T. Yu. Rare metals and deposits thereof. Sorosovskiy obrazovatelnyi zhurnal. 2001. Vol. 7, No. 11. pp. 79–85.
5. Holland H. D., Turekian K. K. Treatise on Geochemistry. 2^nd ed. Amsterdam : Elsevier, 2014. 9144 p.
6. Smith M. P., Moore K., Kavecsánszki D., Finch A. A., Kynicky J., Wall F. From mantle to critical zone: A review of large and giant sized deposits of the rare earth elements. Geoscience Frontiers. 2016. Vol. 7, Iss. 3. pp. 315–334.
7. Goodenough K. M., Schilling J., Jonsson E., Kalvig P., Charles N. et al. Europe’s rare earth element resource potential: An overview of REE metallogenetic provinces and their geodynamic setting. Ore Geology Reviews. 2016. Vol. 72. pp. 838–856.
8. Sarapää O., Al Ani T., Lahti S. I., Lauri L. S., Sarala P. et al. Rare earth exploration potential in Finland. Journal of Geochemical Exploration. 2013. Vol. 133. pp. 25–41.
9. Al-Ani T., Sarapää O. Geochemistry and mineral phases of REE in Jammi carbonatite veins and fenites, southern end of the Sokli complex, NE Finland. Geochemistry: Exploration, Environment, Analysis. 2013. Vol. 13, Iss. 3. pp. 217–224.
10. Mikhailov V. P., Aminov V. N. (Eds.). Mineral and raw material base of the Republic Karelia. Petrozavodsk : Kareliya, 2005. Book 1: Combustible mineral resources. Metallic mineral resources. 280 p.
11. Mikhailov V. P., Aminov V. N. (Eds.). Mineral and raw material base of the Republic Karelia. Petrozavodsk : Kareliya, 2006. Book 2: Non-metallic mineral resources. Underground waters and medical muds. 356 p.
12. Shchiptsov V. V. Industrial minerals of the Tiksheozero-Eletozero alkaline ultramafic-carbonatitic and alkaline gabbroic complexes in Karelia, Russia. Mineral deposit research for a high-tech world : Proceedings of the 12th Biennial SGA Meeting. Uppsala, 2013. Vol. 4. pp. 1781–1783.
13. Kogarko L. N., Ryabchikov I. D. Barium and other incompatible elements in rocks of Eletozero intrusion. Ore Potential of Alkaline, Kimberlite and Carbonatite Magmatism : 31^st International Conference Proceedings. Moscow : GEOKhI RAN, 2014. pp. 51–52.
14. Sharkov E. V., Shchiptsov V. V., Chistyakov A. V., Bogina M. M. Mid-Paleoproterozoic titaniferous Elet’ozersky complex of ultramafic-mafic-alkaline rocks in Northern Karelia (Russia) as transitional chamber of Fe-Ti-alkali basaltic magmatic system. Alkaline Magmatism of the Earth and Related Strategic Metal Deposits : Proceedings of XXXII International Conference. Moscow : GEOKHI RAN, 2015. pp. 107–109.
15. Shchiptsov V. V., Bubnova T. P., Garanzha A. V., Skamnitskaya L. S., Shchiptsova N. I. Technological, geological and economic assessment of resource potential of Tiksheozero carbonates (formation of ultrabasic alkaline rocks and carbonatites). Geology and Minerals of Karelia : Collected Works. Petrozavodsk : KarNTs RAN, 2007. Iss. 10. pp. 159–170.
16. Kuleshevich L. V. Rare-earth mineralization of Tiksheozero–Eletozero alkaline rock mass (Northern Karelia). Geology and Minerals of Karelia : Collected Works. Petrozavodsk : KarNTs RAN, 2016. Iss. 10. pp. 71–87.
17. Khazov R. A., Popov M. G., Biske N. S. Riphean potassium alkaline magmatism in the south of the Baltic Shield. Saint-Petersburg : Nauka, 1993. 216 p.
18. Kuleshevich L. V., Dmitrieva A. V., Khazov R. A. Ba-Sr-P-Ti-TR-feldspar raw materials of Elesenvaara alkaline complex, Karelia: geochemistry and mineralogy of rare-earth elements. Uchenye zapiski Petrozavodskogo gosudarstvennogo universiteta. Ser.: Estestvennye i tekhnicheskie nauki. 2014. No. 4. pp. 67–70.
19. Larin A. M. Rapakivi garnets and associated rocks. Saint-Petersburg : Nauka, 2011. 402 p.