Вестник МГТУ, 2021, Т. 24, № 1.

Хубер М. и др. Изотопные характеристики серы сульфидов Хибинского и Ловозерского массивов. Conclusion The sulfur isotope geochemistry of the two world biggest agpaitic complexes of the Khibina and Lovozero, which are the key magmatic centers of the Paleozoic KAP, provides an opportunity to understand the role of plume-lithosphere interaction processes responsible for the alkaline igneous activity in the north-eastern part of the Fennoscandian Shield. The stable sulfur isotope 534S study has been carried out on the pentlandite ((Fe, Ni)9S8) and pyrite (FeS2) from Khibina nepheline syenite and on the pentlandite ((Fe, Ni)9S8), chalcopyrite (CuFeS2) and pyrite (FeS2) from Lovozero eudialyte-bearing nepheline syenite. The ranges in 534S values are generally large (from +0.69 to +6.30 % VCDT), but vary according to the isotopic fractionation between the sulfide phase and the melt or fluid. Comparison of sulfur-geochemical features of Khibina and Lovozero nepheline syenite with 534S data for the carbonatites from the Khibina, Sallanlatvi, Seblyavr, Vuoriyarvi, Salmagora and Kovdor massifs show later carbonatite formation relatively to associated alkaline rocks. Geochemical sulfur isotope 534S investigations emphasize that parental magmas of the Khibina and Lovozero alkaline massifs were derived from a metasomatized sulfur-enriched (534S of +1 to +6 % VCDT) subcontinental lithospheric mantle (SCLM). We suggest that high-534S signature on the SCLM can be explained by high-534S Archaean crust subduction. Acknowledgments Sulfur isotope analysis was undertaken thanks to the kindness of prof. Stanislaw Halas. This research was funded by the state assignment of GI KSC RAS No. 0226-2019-0053. Conflict of interest The authors declare no conflict of interest. References Arzamastsev, A. A., Arzamastseva, L. V., Zaraiskii, G. P. 2011. Contact interaction o f agpaitic magmas with basement gneisses: An example of the Khibina and Lovozero massifs. Petrology, 19, pp. 109-133. DOI: https://doi.org/10.1134/S0869591111020032. Arzamastsev, A. A., Yakovenchuk, V. N., Pakhomovsky, Ya. A., Ivanyuk, G. Yu. 2008. The Khibina and Lovozero alkaline massifs: Geology and unique mineralization. Apatity, GI KSC RAS. Babiel, R., Marks, M. A. W., Neumann, U., Markl, G. 2018. Sulfides in alkaline and peralkaline rocks: Textural appearance and compositional variations. Neues Jahrbuch fu r Mineralogie-Abhandlungen: Journal o f Mineralogy and Geochemistry, 195(2), pp. 155-175. DOI: https://doi.org/10.1127/njma/2018/0095. Bell, K., Zaitsev, A. N., Spratt, J., Frojdo, S. et al. 2015. Elemental, lead and sulfur isotopic compositions of galena from Kola carbonatites, Russia - implications for melt and mantle evolution. Mineralogical Magazine, 79(2), pp. 219-241. DOI: https://doi.org/10.1180/minmag.2015.079.2.01. Cabral, R. A., Jackson, M. G., Rose-Koga, E. F., Koga, K. T. et al. 2013. Anomalous sulphur isotopes in plume lavas reveal deep mantle storage of Archaean crust. Nature, 496, pp. 490-493. DOI: https://doi.org/10.1038/nature12020. Delavault, H., Chauvel, C., Thomassot, E., Devey, C. W. et al. 2016. Sulfur and lead isotopic evidence of relic Archean sediments in the Pitcairn mantle plume. Proceedings o f the National Academy o f Sciences (PNAS), 113(46), pp. 12952-12956. DOI: https://doi.org/10.1073/pnas.1523805113. Downes, H., Balaganskaya, E., Beard, A., Liferovich, R. et al. 2005. Petrogenetic processes in the ultramafic, alkaline and carbonatitic magmatism in the Kola Alkaline Province: A review. Lithos, 85(1-4), pp. 48-75. DOI: https://doi.org/10.1016/j.lithos.2005.03.020. Ernst, R. E., Bell, K. 2010. Large igneous provinces (LIPs) and carbonatites. Mineralogy and Petrology, 98(1), pp. 55-76. DOI: https://doi.org/10.1007/s00710-009-0074-1. Farquhar, J., Jackson, M. 2016. Missing Archean sulfur returned from the mantle. Proceedings o f the National Academy o f Sciences (PNAS), 113(46), pp. 12893-12895. DOI: https://doi.org/10.1073/pnas.1616346113. Farquhar, J., Nanping, W. U., Canfield, D. E., Oduro, H. 2010. Connections between sulfur cycle evolution, sulfur isotopes, sediments and base metal sulfide deposits. Economic Geology, 105(3), pp. 509-533. DOI: https://doi.org/10.2113/gsecongeo.105.3.509. Giuliani, A., Fiorentini, M. L., Martin, L. A. J., Farquhar, J. et al. 2016. Sulfur isotope composition of metasomatized mantle xenoliths from the Bultfontein kimberlite (Kimberley, South Africa): Contribution from subducted sediments and the effect of sulfide alteration on S isotope systematics. Earth and Planetary Science Letters, 445, pp. 114-124. DOI: https://doi.org/10.1016Zj.epsl.2016.04.005. Goodenough, K. M., Upton, B. G. J., Ellam, R. M. 2002. Long-term memory of subduction processes in the lithospheric mantle: Evidence from the geochemistry of basic dykes in the Gardar Province of South Greenland. Journal o f the Geological Society, 159(6), pp. 705-714. DOI: http://dx.doi.org/10.1144/0016- 764901-154. 86