Abstract

The Sveconorwegian pegmatite province is one of the world's largest pegmatite provinces, containing more than 5000 pegmatites. The niobium-yttrium-fluorine (NYF)-signature pegmatites were emplaced in the Sveconorwegian orogen (1.1–0.9 Ga) and are divided into seven pegmatite fields. The Tørdal and Evje-Iveland pegmatite fields contain the most evolved pegmatites, with micas having atomic K/Rb ratios down to 3, while the most evolved pegmatites, in Froland, have K/Rb ratios down to 23. The highly fractionated pegmatites in Evje-Iveland and Tørdal contain Li-bearing micas classified as Li-muscovite–polylithionite (Evje-Iveland) and siderophyllite–polylithionite and polylithionite (Tørdal), with up to 7.7 wt.% Li2O in the latter. The muscovite-trilithionite and polylithionite–trilithionite formed in “cleavelandite” replacement zones with a lithium-caesium-tantalum (LCT) signature. The Li-rich micas in Tørdal are highly enriched in Ta, Sc, and Sn with up to 337 ppm Ta, 2806 ppm Sc, and 807 ppm Sn. The trace element concentrations are different for Tørdal and Evje-Iveland, which could suggest a different source for the Tørdal pegmatite melts than for the Evje-Iveland melts. The Evje-Iveland melts are thought to be of anatectic origin.

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