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The first data on the Late Riphean age by U–Pb and Sm–Nd analysis (≥922 ± 14 and 686 ± 19 Ma, respectively) were obtained for rocks of the dunite–clinopyroxenite–gabbro complex of the Chistop massif in the Patinum-bearing Belt of the Urals. These data allow one to assume that the formation of the Ural paleoocean probably started immediately after the break-up of Rodinia. 相似文献
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Sychev S. N. Khudoley A. K. Lebedeva O. Yu. Rogov A. V. Sokolov S. D. Chamberlain K. R. Maklashin V. S. Lvov P. A. 《Doklady Earth Sciences》2020,494(2):762-766
Doklady Earth Sciences - U–Pb dating of zircons from granitoids located within the Rassokha terrane show a Silurian age of their formation. Younger dates from one of the samples are related... 相似文献
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New U?Pb (SHRIMP II) data on the age (2661.8 ± 7.1 Ma) and isotopic (Sm?Nd) composition of the Patchemvarek gabbro?anorthosite massif located in the junction zone between the Neoarchean Kolmozero-Voron’ya greenstone belt and Keivy paragneiss structure are discussed. The established age and geological?tectonic position of gabbro?anorthosites allow the prognostic metallogenic estimate of Ti?V?Fe mineralization to be extended to the entire Kolmozero-Voron’ya?Keivy infrastructural zone of the Kola?Norwegian province of the Fennoscandian shield. 相似文献
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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). 相似文献
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Solar System Research - The groups of asteroids which can have approaches to two or more planets have been determined. It is shown that in the phase space of the orbital elements there are regions... 相似文献
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Rytsk E. Yu. Velikoslavinsky S. D. Kuznetsov A. B. Tolmacheva E. V. Rodionov N. V. Berezhnaya N. G. Lvov P. A. Bogomolov E. S. Andreev A. A. Fedoseenko A. M. 《Doklady Earth Sciences》2023,507(3):S406-S413
Doklady Earth Sciences - The results of geochronological study (U–Pb SHRIMP-II) of zircons from granodiorites and plagiogranites of the main phase of the Tallai pluton of the... 相似文献
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