Myskova T.A.,Russian Academy of Sciences |
Ivanov N.M.,GGUP SF Mineral |
Korsakova M.A.,GGUP SF Mineral |
Milkevich R.I.,Russian Academy of Sciences |
And 2 more authors.
Stratigraphy and Geological Correlation | Year: 2012
During this work, the composition of Sariolian volcanites of the Vermas formationin the Karelian region was studied and the U-Pb age of these rocks was first obtained (SHRIMP-II). In composition these volcanites are andesites and andesite-basalts, as well as, to a lesser extent, trachyandesites and trachyandesitobasalts of the calc-alkaline series. Due to porphyroblast crystallization, widely manifested in this region volcanites are enriched in TiO 2, Al 2O 3, Fe 2O 3total, K 2O, Rb, Cs, Zr, Hf, Y, Nb, Cr, V, Th and REE (primarily La and Ce). Rocks of the Vermas formation formed in the Paleoproterozoic (2412 ± 17 Ma) and were transformed as a result of the Svecofennian metamorphism in the interval of 1970 ± 15 Ma. The source of the melt and inherited zircons with the age of 2630-2760 Ma can be crustal material with the ancient Sm-Nd model age (3-3. 1 Ga). © 2012 Pleiades Publishing, Ltd.