Isotopic timing of the magmatic and metamorphic events at the turn of the Archean and Proterozoic within the Belomorian belt, Fenno-Scandinavian shield
| Autor: | V. A. Glebovitskii, I. S. Sedova, N. G. Berezhnaya, A. N. Larionov |
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| Rok vydání: | 2017 |
| Předmět: |
Proterozoic
020209 energy Archean Metamorphic rock Geochemistry Metamorphism 02 engineering and technology 010502 geochemistry & geophysics Migmatite 01 natural sciences 0202 electrical engineering electronic engineering information engineering Earth and Planetary Sciences (miscellaneous) General Earth and Planetary Sciences Protolith Geology 0105 earth and related environmental sciences Gneiss Zircon |
| Zdroj: | Doklady Earth Sciences. 476:1143-1146 |
| ISSN: | 1531-8354 1028-334X |
| DOI: | 10.1134/s1028334x1710004x |
| Popis: | It is proved that dating high-grade metamorphism events through dating of migmatites is quite efficient. Our investigation has made it possible to identify two events of 2500 and 2700 Ma and to estimate the age of an igneous protolith for both tonalite gneiss, the most ancient in the Belomorian belt, and related metagabbroid. Based on the upper crossing of the concordia and the discordia, the zircon core age is estimated at 2796 ± 63 Ma; this age is slightly different from that of a growth rim of rhythmically zoned prismatic zircon (2816 ± 110 Ma). A linear approximation of all measured points yields an upper crossing of 2803 ± 55 Ma. The error of these estimates is high for quite understandable reasons, and yet it should be taken into account when analyzing the geodynamic development regimes of Neo-Archaean endogenic processes. |
| Databáze: | OpenAIRE |
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