The Composition and Age of the Mesoarchean Gabbro in the South Vygozersky and Kamennoozersky Greenstone Structures, Karelia
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The geochemical and zircon geochronological (U-Pb, SHRIMP-II) study of Mesoarchean gabbros of the South Vygozersky and Kamennoozersky greenstone structures of Central Karelia made it possible to distinguish four gabbro types: (1) Fe–Ti gabbro, 2869 ± 12 Ma, (2) gabbro compositionally close to tholeiitic basalts, 2857 ± 7 Ma, (3) leucogbabbro, 2840 ± 5 Ma; and (4) melanogabbro, 2818 ± 14 Ma. From the early to late gabbros, the rocks are depleted in Ti, Fe, V, Y, Zr, Nb, Hf, REE and enriched in Mg, Ca, Cr, Ni. According to the systematics (Condie, 2005), the Nb/Y, Zr/Y, Zr/Nb ratios in the studied Late Archean gabbros are close to those of primitive mantle, while the gabbros in composition are similar to those of plumederived ocean-plateau basalts. Their magma sources were derived from different mantle reservoirs. The leucogabbro and melanogabbro with similar εNd = +4 were derived from a depleted mantle source (DM). The gabbro close in composition to tholeiitic basalts and having the elevated positive εNd (+4.9) was derived from a strongly depleted mantle source. Insignificant admixture of crustal material or lithospheric mantle is inferred in a source of the Fe–Ti gabbro (with lowest εNd = +2.1).
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- Frolova, T.I. and Burikova, I.A., Magmaticheskie formatsii sovremennykh geotektonicheskikh obstanovok (Magmatic Formations of the Modern Geotectonic Settings), Moscow: MGU, 1997.Google Scholar
- Gosudarstvennaya geologicheskaya karta RF masshtaba 1: 200000. Izdanie vtoroe. Seriya Karel’skaya. List R-36-XII (Medvezh’egorsk). Ob"yasnitel’naya zapiska (State Geological Map of the RF on a Scale 1: 200000. 2nd Edition. Karel’skaya Series. Sheet R-36-XII (Medvezh’egorsk). Explanatory Notes), St. Petersburg: VSEGEI, 2013.Google Scholar
- Hoskin, P.W.O., Minor and trace element analysis of natural zircon (ZrSiO4) by SIMS and laser ablation ICPMS: a consideration and comparison of two broadly competitive techniques, J. Trace Microprobe Technol., 1998, vol. 16, pp. 301–326.Google Scholar
- Lobach-Zhuchenko, S.B., Arestova, N.A., Chekulaev, V.P., et al., Evolution of the Yuzhno-Vygozero greenstone belt, Karelia, Petrology, 1999, vol. 7, no. 2, pp. 160–176.Google Scholar
- Ludwig, K.P., SQUID1.00. A User’s manual, Berkley Geochronol. Center, Sp. Publ., 2000, no. 2.Google Scholar
- Ludwig, K.P., Isoplot/Ex. A User’s Manual Berkley Geochronol. Center, Sp. Publ., 2001, no. 1a.Google Scholar
- Puchtel, I.S., Hofmann, A.W., Amelin, Yu.V., et al., Combined mantle plume-island arc model for the formation of the 2.9 Ga Sumozero–Kenozero greenstone belt, SE Baltic Shield: isotope and trace element constraints, Geochim. Cosmochim. Acta, 1999, vol. 63, no. 21, pp. 3579–3595.CrossRefGoogle Scholar
- Rannii dokembrii Baltiiskogo shchita (Early Precambrian of the Baltic Shield), SPb.: Nauka, 2005.Google Scholar
- Samsonov, A.V., Bogina, M.M., Bibikova, E.V., et al., The relationship between adakitic, calc-alkaline volcanic rocks and TTGs: implications for the tectonic setting of the Karelian greenstone belts, Baltic Shield, Lithos, 2005, vol. 79, pp. 83–106.Google Scholar
- Smirnov, V.K., Sobolev, A.V., Batanova, V.G., et al., Quantitative SIMS analysis of melt inclusions and host minerals for trace elements and H2O, EOS Transl. AGU, Spring Meet. Suppl., 1995, vol. 76, no. 17.Google Scholar
- Sochevanov, N.N., Arestova, N.A., Matrenichev, V.A., et al., First data on Sm-Nd age of the Archean basalts in the Karelian granite–greenstone terrane, Dokl. Akad. Nauk SSSR, 1991, vol. 318, no. 1, pp. 175–180.Google Scholar