Rare earth exploration potential in Finland

Abstract

Exploration for economic deposits of rare earth elements (REEs) is currently active all over the world. In this case the REE potential of Finland was evaluated by analysing existing relevant data (literature, databases, and drill cores) combined with new geochemical surveys and drillings of new targets. Yttrium and lanthanum contents in the regional till and rock geochemical databases of the GTK show regional anomalies for the Paleoproterozoic Tana Belt and the Central Lapland granitoid complex in northern Finland and the Mesoproterozoic rapakivi granite areas in southern Finland. Local lanthanum anomalies are observed also for the Devonian Sokli carbonatite complex and the Paleoproterozoic Korsnäs and Otanmäki areas that seem to be the most promising of the current REE prospects in Finland. The highest REE concentrations are in the carbonatite veins of the Korsnäs Pb–REE-mine (0.9%) and the alkaline gneiss in Otanmäki, central Finland (2.4%). Among the new prospects the highest concentrations of REE are in the fenite zone of the Sokli carbonatite complex (1–2%) and in the Kovela monazite–granite in southern Finland (0.5–4.3%). Other studied prospects and small showings with anomalous REE-contents are associated with carbonatites, alkaline rocks, appinites, arkosic gneisses, albitites, rapakivi granites and granite pegmatites. Typical REE-bearing minerals in the targets include monazite, ancylite, bastnaesite, allanite, xenotime, apatite and zircon.