Paleoproterozoic (2.51–2.40 Ga) Igneous Provinces of the Northeastern Fennoscandia: Geochemistry of Volcanic Rocks and Correlation with Intrusive Complexes

Abstract

The results of geochemical studies of Paleoproterozoic volcanic rocks in the structure of the Polmak–Pechenga–Imandra–Varzuga belt of the northeastern part of the Fennoscandian Shield are presented. Taking into account new geochronological data, the volcanic series are correlated with subvolcanic and intrusive rocks of the Murmansk and Kola–Norwegian terranes. The comparative analysis of sections of volcanic rocks of the Imandra–Varzuga and Pechenga structures indicate asynchronous evolution of these fragments of the belt in a range of 2.51–2.40 Ga and a significant time gap (probably, >300 m.y.) in evolution of both the Imandra–Varzuga and Pechenga structures. The geochemical evidence is provided for the cyclic plume-lithospheric interaction during magmatism of the Sumian–Sariolian period, which shows that basic melts mostly generated from facies of spinel lherzolites exhibit features of significant crustal contamination as a result of their interaction with rocks of the Archean basement.