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Origin and Exploration of the Kola PGE‐bearing Province

2019; American Geophysical Union; Linguagem: Inglês

10.1002/9781119290544.ch1

2328-8779

Ф. П. Митрофанов, T. B. Bayanova, John Ludden, Alexey Korchagin, В. В. Чащин, Lyudmila I. Nerovich, Pavel Serov, Alexander F. Mitrofanov, Dmitry Zhirov,

earthquake and tectonic studies

The NE Fennoscandian Shield comprises the Northern (Kola) Belt in Finland and the Southern Belt in Karelia. The belts host mafic-ultramafic layered Cu-Ni-Cr and Pt-Pd-bearing intrusions. They were studied using precise isotope analyses with U-Pb on zircon and baddeleyite and Sm-Nd on rock-forming silicates and sulfides. The analyses indicate the 130 Ma magmatic evolution with major events at 2.53, 2.50, 2.45, and 2.40 Ga. It is considered to be governed by the long-lived mantle plume activity. Barren phases were dated at 2.53 Ga for orthopyroxenites and olivine gabbro in the Fedorovo-Pansky massif. Main PGE-bearing phases of gabbronorite (Mt. Generalskaya), norite (Monchepluton), and gabbronorites (Fedorovo-Pansky and Monchetundra massifs) yielded ages of 2.50 Ga. Anorthosites of Mt. Generalskaya, the Fedorovo-Pansky and Monchetundra massifs occurred at the 2.45 Ga PGE-bearing phase. According to regional geochronological correlations, this widespread event emplaced layered PGE-bearing intrusions of Finland (Penikat, Kemi, Koitelainen) and mafic intrusions in Karelia. Dikes of the final mafic magmatic pulse at 2.40 Ga are present in the Imandra lopolith. Slightly negative εNd values and ISr values of 0.703–0.704 suggest the layered intrusions to originate from an enriched EM-1-like mantle reservoir.