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Artem V. Mokrushin
Artem V. Mokrushin
Senior Researcher, Ph.D.
Geological Institute of the Kola Science Centre, Russian Academy of Sciences
Senior Researcher, Ph.D.
Geological Institute of the Kola Science Centre, Russian Academy of Sciences
Apatity
Russia

Articles

Geology
  • Date submitted
    2022-04-11
  • Date accepted
    2022-06-15
  • Date published
    2022-07-26

Magma feeding paleochannel in the Monchegorsk ore region: geochemistry, isotope U-Pb and Sm-Nd analysis (Kola region, Russia)

Article preview

A comprehensive study of a 340 m thick lenticular-sheet body of ultramafic composition penetrated by structural well M-1 at a depth of about 2.2 km was accomplished. Its main volume is composed of plagioharzburgite; fine-grained rocks of norite and orthopyroxenite chilling zones are preserved on endocontacts. The rocks of the body are similar in composition to the rocks near the underlying ore-bearing layered intrusion – the Monchepluton. The age of intrusion of the ultramafic body is 2510 ± 9 Ma (U-Pb, ID-TIMS, zircon) and, taking into account analytical errors, is comparable with the formation period of the Monchepluton (2507-2498 Ma). According to the study of the Sm-Nd system in rocks and minerals, a positive value of the e Nd (+1.1) parameter was established, similar to that in dunites and chromitites of the Monchepluton. Based on these results, the ultramafic body penetrated at depth was assigned to the magma feeding paleochannel through which the ultramafic, weakly contaminated magma entered the overlying magma chamber. This body is a unique example of a magma-feeding system for the ore-bearing layered intrusion of Precambrian age.

How to cite: Smolkin V.F., Mokrushin A.V., Bayanova T.B., Serov P.A., Ariskin A.A. Magma feeding paleochannel in the Monchegorsk ore region: geochemistry, isotope U-Pb and Sm-Nd analysis (Kola region, Russia) // Journal of Mining Institute. 2022. Vol. 255. p. 405-418. DOI: 10.31897/PMI.2022.48