Rare earth elements in phoscorites and carbonatites of the Devonian Kola Alkaline Province, Russia: Examples from Kovdor, Khibina, Vuoriyarvi and Turiy Mys complexes

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• 作者：Anatoly N. Zaitsev^a ; ^b ; ^{burbankite@gmail.com" class="auth_mail} ; C. Terry Williams^b ; Teresa E. Jeffries^b ; Stanislav Strekopytov^b ; Jacques Moutte^c ; Olga V. Ivashchenkova^a ; John Spratt^b ; Sergey V. Petrov^d ; Frances Wall^e ; Reimar Seltmann^b ; Alexey P. Borozdin^d
• 关键词：Rare earth elements ; Rare earth minerals ; Phoscorites ; Carbonatites ; Kola Alkaline Province
• 刊名：Ore Geology Reviews
• 出版年：September, 2014
• 年：2014
• 卷：61
• 期：Complete
• 页码：204-225
• 全文大小：2263 K

文摘

The Devonian (ca. 385-360 Ma) Kola Alkaline Province includes 22 plutonic ultrabasic-alkaline complexes, some of which also contain carbonatites and rarely phoscorites. The latter are composite silicate-oxide-phosphate-carbonate rocks, occurring in close space-time genetic relations with various carbonatites. Several carbonatites types are recognized at Kola, including abundant calcite carbonatites (early- and late-stage), with subordinate amounts of late-stage dolomite carbonatites, and rarely magnesite, siderite and rhodochrosite carbonatites. In phoscorites and early-stage carbonatites the rare earth elements (REE) are distributed among the major minerals including calcite (up to 490 ppm), apatite (up to 4400 ppm in Kovdor and 3.5 wt.% REE₂O₃ in Khibina), and dolomite (up to 77 ppm), as well as accessory pyrochlore (up to 9.1 wt.% REE₂O₃) and zirconolite (up to 17.8 wt.% REE₂O₃). Late-stage carbonatites, at some localities, are strongly enriched in REE (up to 5.2 wt.% REE₂O₃ in Khibina) and the REE are major components in diverse major and minor minerals such as burbankite, carbocernaite, Ca- and Ba-fluocarbonates, ancylite and others. The rare earth minerals form two distinct mineral assemblages: primary (crystallized from a melt or carbohydrothermal fluid) and secondary (formed during metasomatic replacement). Stable (C-O) and radiogenic (Sr-Nd) isotopes data indicate that the REE minerals and their host calcite and/or dolomite have crystallized from a melt derived from the same mantle source and are co-genetic.