Neoarchaean alkaline rocks of the Central-Kola block - the Chagveuaive massif: geology and age

Petrovskiy M. N., Petrovskaya L. S.

Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2018. V. 147. N 1. P. 44-54

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Language: Russian

Abstract

The article presents the results of geological, geochronological and isotope-geochemical studies of the Chagveuaive alkaline massif in the Kola Alkaline Province. The massif consists of clinopyroxenites and nepheline syenites (the first phase); alkaline syenites, quartz syenites and their pegmatites (second phase); alkaline albite quartz syenites and granosyenites, as well as zirconium quarzolites (the third phase). The rocks are of Neoarchaean age. The crystallization ages determined by the U-Pb method for zircons are 2667  4 Ma for the alkaline syenites of the second phase, and 2601  12 Ma for the third-phase quarzolites. According to their isotope-geochemical Sm-Nd and Rb-Sr characteristics, the rocks of the Chagveuaive alkaline massif have a mantle origin, and the source of their melts was apparently the mantle of the BSE type.

Key words: neoarchaean, Kola Alkaline Province, nepheline syenites, alkaline syenites, mantle.