Abstract
Most of the Precambrian ultramafîcs of northern Finland underwent metamorphic recrystallization and deformation. The rock types have altered to serpentinites, metaperidotites and carbonate-bearing ultramafîcs. Also the accessory ore minerals of the ultramafîcs altered and recrystallized. Hence the present sulphide assemblages include pentlandite, awaruite, heazlewoodite, millerite and mackinawite instead of the common pyrrhotite-pentlandite assemblage of the primary magmatic deposits. Accessory nickel arsenides characterize the carbonatized ultramafîcs. The oxide minerals are chromite, magnetite and ilmenite. Chromites have two kinds of zoning, called the iron-trend and the aluminium-trend correspondingly. The iron-trend of zoning was formed in deuteric reactions of early chromites or the chromite crystals were mantled by secondary magnetite in serpen-tinization. The fine-grained intergrowths of chromite and secondary magnetite exist locally between the chromite core and secondary magnetite; also ilmenite exsolution lamellae exist in some chromites and chromite-magnetite lamellae have rarely been met with in primary ilmenite grains.
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References
Eckstrand OR (1975) The Dumont serpentinite: a model for control of nickeliferous opaque mineral assemblages by alteration reactions in ultramafic rocks. Econ Geol 70:183–201
Evans BW, Frost RB (1975) Chrome-spinel in progressive metamorphism a preliminary analysis. Geochim Cosmochim Acta 39:959–972
Evans BW, Trommsdorff V (1974) On elongate olivin of metamorphic origin. Geology 2:131–132
Gorbunov GI, Jakolev JuU, Astafjev JuA, Goncarov JuV, Bartenev IS, Neradovskii JN (1973) Atlas tekstur i struktur sulfidnyh medno-nikolovyh vud Koskogo poluostrova. Akad Nauk SSSR, Izd NAUKA, Leningrad
Groves DI, Keays RR (1979) Mobilization of ore-forming elements during alteration of dunites, Mt. Keith-Betheno, Western Australia. Can Miner 17:373–390
Groves DI, Barret FM, Binns RA, McQueen KG (1977) Spinel phases associated with metamorphosed volcanic-type iron-nickel sulfide ores from Western Australia. Econ Geol 72:1224–1244
Haggerty SE (1976) Opaque mineral oxides in terrestrial igneous rocks. In: Rumble III D (ed) Oxide Minerals. Miner Soc Am Short Course Not 3:101 – 300
Häkli TA (1971) Silicate nickel and its applications to the exploration of nickel ores. Geol Soc Fin Bull 43:247–263
Idman H (1980) Lapin ultramafiittien oksidifaasista. M Sc Thesis, Univ Turku, Finland
Kaaden Gvd, Ottemann J, Sahoo KR (1972) Chromite verschiedener Zusammensetzung und Genese aus einem Dunit von Saruabil, Sukinda, Orissa (Indian). Neues Jahrb Mineral Monatsh 1972:256–262
Meriläinen K (1976) The granulite complex and adjacent rocks in Lapland, northern Finland. Geol Surv Fin Bull 281:5–119
Nickel EH, Hudson DR (1976) The replacement of chrome spinel by chromian valleriite in sulphide-bearing ultramafic rocks in Western Australia. Contrib Mineral Petrol 55:265–277
Ohnmacht W (1974) Petrogenesis of carbonate-orthopyroxenites (sagvandites) and related rocks from Troms, Northern Norway. J Petrology 15:303–324
Onyeagocha AC (1974) Alteration of chromite from the Twin Sisters dunite, Washington. Am Mineral 59:608–612
Papunen H (1970) Sulphide mineralogy of the Kotalahti and Hiturna nickel-copper ores, Finland. Ann Acad Sci Fenn Ser A III 109:1–74
Papunen H, Idman H, Dvonen E, Neuvonen KJ, Pihlaja P, Talvitie J (1977) Lapin ultramafiiteista (Summary: The ultramaflcs of Lapland). Geol Surv Fin Rep Invest 23
Papunen H, Häkli TA, Idman H (1979) Geological geochemical and mineralogical features of sulfide-bearing ultramafic rocks in Finland. Can Mineral 17:217–232
Ramdohr P (1967) A widespread mineral association, connected with serpentinization. Neues Jahrb Mineral Abh 117:241–265
Schreyer W, Ohnmacht W, Mannchen J (1972) Carbonate orthopyroxenites (sagvandites) from Troms northern Norway. Lithos 5:345–364
Simonen A (1971) Das finnische Grundgebirge. Geol Rundsch 60:1406–1421
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© 1982 Springer-Verlag Berlin Heidelberg
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Papunen, H., Idman, H. (1982). Ultramafic Rocks and Related Ore Minerals of Lapland, Northern Finland. In: Amstutz, G.C., et al. Ore Genesis. Special Publication of the Society for Geology Applied to Mineral Deposits, vol 2. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-68344-2_37
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DOI: https://doi.org/10.1007/978-3-642-68344-2_37
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