Scientific publications

The Vokshozero structure is located in the southernmost Keret greenstone belt, which, together with the Tikshozero belt, is part of the North Karelian greenstone belt system of the Belomorian greenstone belt. Recognized within the belts are at least three different-aged greenstone complexes: one Mesoarchean Keretozero (2.88–2.83 Ga) complex and several Neoarchean, namely Hizovaara-1 (2.8–2.78 Ga), Chelozero (2.76 Ga) and Hizovaara-2 (ca.2.70 Ga). Geochronological studies, carried out on an ion microprobe, have shown that a rhyodacite sample is dominated by zircons dated at 1837 ± 37 Ma, a stage at which the rock was metamorphosed. At the same time, a zircon grain dated at 2829 ± 37 Ma, a magmatic stage in rock formation, was revealed. Metabasalts of the Upper Kumozero STA correspond in composition to tholeiites. Their LREE spectra exhibit a gently dipping distribution pattern with minor LREE impoverishment and nonfractionated HREE spectra. As their spidergrams have a negative Th anomaly but no Nb and Ti anomalies, they can be correlated with oceanic plateau rocks. Intermediate to felsic volcanics from the Khattomozero STA of the Vokshozero structure are correlated with mature island-arc volcanics. Their composition suggests formation in sources of magmatism, located on different levels, and a gradual growth of the continental crust.