The Great Dyke of the Kola Peninsula as a Marker of an Archean Cratonization in the Northern Fennoscandian Shield

The results of geochronological and petrological studies of the largest mafic dyke in the northern part of the Fennoscandian Shield, called the Great Dyke of the Kola Peninsula (GDK), are presented. According to U-Pb D-TIMS baddeleyite dating, the GDK crystallization age is 2680 ± 6 Ma. The age of h...

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Bibliographic Details
Published in:Petrology 2022-12, Vol.30 (6), p.591-609
Main Authors: Stepanova, A. V., Samsonov, A. V., Salnikova, E. B., Egorova, S. V., Larionova, Yu. O., Arzamastsev, A. A., Larionov, A. N., Sukhanova, M. A., Veselovskiy, R. V.
Format: Article
Language:English
Subjects:
Asthenosphere
Cratons
Crystallization
Dating
Earth and Environmental Science
Earth Sciences
Gabbro
Garnet
Geochemistry
Geochronology
Geochronometry
Injection
Isotopes
Lead
Lithosphere
Low concentrations
Magma
Magnesium
Melts
Mineralogy
Plagioclase
Radiometric dating
Rock intrusions
Zircon
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Summary:The results of geochronological and petrological studies of the largest mafic dyke in the northern part of the Fennoscandian Shield, called the Great Dyke of the Kola Peninsula (GDK), are presented. According to U-Pb D-TIMS baddeleyite dating, the GDK crystallization age is 2680 ± 6 Ma. The age of host granites is 2.75–2.72 Ga (U-Pb, zircon, SHRIMP-II). The dyke has a simple internal structure with no signs of multistage melt injection. It comprises equigranular and plagioclase-porphyritic dolerites and gabbro that are amphibolitized to varying degrees. All rocks are low-Mg (Mg# less than 0.37) with low concentrations of Cr and Ni, and were derived through differentiation of more primitive melts. The analysis of geochemical and Sr-Nd isotopic data suggests that GDK melts could be formed by mixing of two types of mantle melts: depleted asthenospheric melt and enriched melt formed via melting of a lithospheric mantle. The weakly fractionated HREE patterns indicate that primary GDK melts originated at shallow (
ISSN:0869-5911
1556-2085
DOI:10.1134/S086959112206008X