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Vol. 3 (2000 year), No. 2

Kislitsyn R.V., Balagansky V.V., Manttari I., Gannibal L.F., Pozhilenko V.I.
U-Pb zircon age from gabbronorites and gabbroanorthosites of the Voche-Lambina study area, the Kola Peninsula

The Voche-Lambina study area is located within the Voche-Lambina Shear Zone (VLSZ), which is a part of a shear zone system that separates the Belomorian and Central-Kola Terranes. The emplacement of gabbronorite and gabbroanorthosite of the Main Fault Zone is connected to the initiation of the VLSZ. An upper intercept age of magmatic zircons from the gabbronorite is 2491В±13 Ma, which we interpret as the time of the initiation of the VLSZ. An upper intercept age of metamorphic zircons from the gabbroanorthosite is 2403В±7 Ma. This age dates the first shearing and metamorphic reworking, which took place simultaneously with those of the Main Ridge Gabbro-Anorthosite Massif (2406В±3 Ma). The isotopic dates obtained suggest that the VLSZ originated at the initial Palaeoproterozoic rifting 2.4-2.5 Ga ago. From published data, the Kolvitsa Shear Zone originated at the same time span; thus, the VLSZ and the Kolvitsa Shear Zone are components of one Palaeoproterozoic system of shear zones.

(in Russian, стр.8, fig. 3, tables. 1, ref 40, MS Word 95, MS Word 95 171 Kb)