ISSN 1075-7015, Geology of Ore Deposits, 2010, Vol. 52, No. 8, pp. 843–851. © Pleiades Publishing, Ltd., 2010. Original Russian Text © D.R. Zozulya, E.E. Savchenko, K. Kullerud, E.K. Ravna, L.M. Lyalina, 2010, published in Zapiski RMO (Proceedings of the Russian Mineralogical Soci- ety), 2010, No. 2, pp. 101–112. 843 INTRODUCTION An unusual ultrapotassic dike was recently found on Kvalöya Island (Northern Norway) in the Precam- brian basement of the Western Tromsö (Zozulya et al., 2008). The basement is composed of Archean and Paleoproterozoic rocks of the so-called “window” 120 × 20 km in size in the Caledonides (Fig. 1), basically consisting of tonalite–trondhjemite–granodiorite associations (2.9–2.6 Ga), greenstone belts (2.84– 2.60 Ga), a complex of mafic dikes (2.4 Ga), and gab- brodiorite and granite intrusions (1.8–1.7 Ga) (Kullerud et al., 2006a, 2006b). The dike crops out in a road cutting, is 0.3–0.4 m thick and is traced westward for a few hundred meters. A linear belt of dikes similar in petrography that are 0.1 to 1.0 m thick extends in the same direction for four kilometers to the west of the first finding. The dikes cut through granites 1.8 Ga in age. The country rocks are disintegrated and fractured at a distance of 1 m from the contact with the dikes, indicating the high dynamic conditions of emplacement. The rock is porphyritic, with phlogopite phenoc- rysts 1–5 mm in size (up to 5 vol %). Phlogopite is Corresponding author: D.R. Zozulya. E-mail: zozu- lya@geoksc.apatity.ru occasionally zonal with tetraferriphlogopite in the outer zone distinguished by an inverse scheme of ple- ochroism. The groundmass is composed (vol %) of potassic magnesioarfvedsonite (~30), orthoclase (40– 50), apatite (5–7), baotite (up to 3), rutile (1–3), zir- con, quartz, and barite. Some samples contain single grains of Ti-bearing aegirine, magnesian mica with an extremely low Al 2 O 3 content (1–2 wt %), and uniden- tified Na–Mg–Ba phosphate. Chlorite (5–7 vol %) is a secondary mineral. The composition of the rock-forming minerals (4.5–6.0 wt % K 2 O and 0.7–3.5 wt % TiO 2 in magne- sioarfvedsonite, 1.6–3.6 wt % FeO in orthoclase, 9.2– 10.7 wt % Al 2 O 3 and 2.1–2.6 wt % TiO 2 in phlogopite (Table 1)) and the bulk chemical composition of the rock (K/Na = 2.3–2.9, K/Al = 1.0–1.2, (Na + K)/Al = 1.4–1.7, Mg# 65–73, (La/Yb) n = 100–140, 3.2–4.0 wt % TiO 2 , 0.55–1.47 wt % BaO, 2.5–3.0 wt % P 2 O 5 , 2650–3000 ppm Zr, 900–1260 ppm REE total, 2300– 2500 ppm Sr, 270–350 ppm Cr, and 240–320 ppm Ni (Zozulya et al., 2008)) allow us to classify the rock as mafic or intermediate lamproite (Bogatikov et al., 1991), or lamproite of the transitional type (Sheppard and Taylor, 1992). In petrochemistry, the Kvalöya dike also corresponds to minette—a lamprophyre of inter- mediate composition; however, the absence of plagio- Unique Accessory Ti–Ba–P Mineralization in the Kvalöya Ultrapotassic Dike, Northern Norway D. R. Zozulya a , E. E. Savchenko a , K. Kullerud b , E. K. Ravna b , and L. M. Lyalina a a Geological Institute, Kola Scientific Center, Russian Academy of Sciences, ul. Fersmana 14, Apatity, 184209 Russia b Department of Geology, Tromsø University, Tromsø N-9037, Norway Received March 17, 2009 Abstract—Unusual ultrapotassic dikes were recently found on the Kvalöya Island in Northern Norway. The dikes crosscutting granites 1.8 Ga in age are 0.1–1.0 m thick and consist of phlogopite phenocrysts in a fine- grained groundmass of K-magnesioarfvedsonite, orthoclase, apatite, and secondary chlorite. According to the composition of the rock-forming minerals (4.5–6.0 wt % K 2 O and 0.7–3.5 wt % TiO 2 in magnesioarfved- sonite, 1.6–3.6 wt % FeO in orthoclase, 9.2–10.7 wt % Al 2 O 3 and 2.1–2.6 wt % TiO 2 in phlogopite) and its bulk chemical composition (K/Na = 2.3–2.9, K/Al = 1.0–1.2, (Na + K)/Al = 1.4–1.7, Mg# V = 65–73, (La/Yb) n = 100–140, 3.2–4.0 wt % TiO 2 , 0.55–1.47 wt % BaO, 2.5–3.0 wt % P 2 O 5 , 2650–3000 ppm Zr, 900–1260 ppm REE total, 2300–2500 ppm Sr), the rock corresponds to lamproite of the transitional type. The unique chemical composition of the rock resulted in uncommon Ti–Ba–P accessory mineralization, including baotite Ba 4 (Ti,Nb) 8 Si 4 O 28 Cl (up to 5 vol %), Sr-apatite (5–7 vol %), and previously unknown Na– Mg–Ba phosphate. Baotite forms anhedral elongated and isometric grains 10–500 μm in size. It is charac- terized by low Nb (0.03–0.05 f.c.); admixtures of K (0.04–0.12 f.c.) and Sr (0.04–0.07) replacing Ba and Fe (0.01–0.03 f.c.); and Al (0.03–0.04 f.c.) substituting Ti. Euhedral elongated zonal apatite crystals are extremely enriched in SrO (8–12 wt %) and REE 2 O 3 + Y 2 O 3 (6–9 wt %) in the marginal zone. Na–Mg–Ba phosphate occurs as prismatic grains 10–100 μm in size. The atomic ratio of its major cations Na : Mg : Ba : P ~ 2 : 1 : 1: 2 corresponds to the conventional formula Na 2 MgBa(PO 4 ) 2 ; the mineral contains Sr, Mn, Fe, Ca, Si, and Al admixtures. DOI: 10.1134/S1075701510080167 MINERALS AND PARAGENESES OF MINERALS