Geochemical and Sr–Nd Isotope Systematics of the Late Permian–Early Triassic Traps from the Kuznetsk Basin: Magma Sources and Correlation with the Noril’sk Region Volcanics

The study provides whole-rock geochemical and Rb–Sr and Sm–Nd isotope examinations of Permian–Triassic volcanics (basalts, basaltic andesites) and sills (trachydolerites, monzodiorites) from the Kuznetsk Basin, which is part of the Siberian Large Igneous Province. It is shown that the volcanic secti...

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Bibliographic Details
Published in:Doklady earth sciences 2023-06, Vol.510 (2), p.400-410
Main Author: Svetlitskaya, T. V.
Format: Article
Language:English
Subjects:
Andesite
Basalt
Carbonates
Earth and Environmental Science
Earth Sciences
Gadolinium
Geochemistry
Isotope composition
Isotopes
Lava
Magma
Permian
Rock
Rocks
Sequencing
Sills
Strontium 87
Strontium isotopes
Subduction
Systematics
Titanium dioxide
Triassic
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Summary:The study provides whole-rock geochemical and Rb–Sr and Sm–Nd isotope examinations of Permian–Triassic volcanics (basalts, basaltic andesites) and sills (trachydolerites, monzodiorites) from the Kuznetsk Basin, which is part of the Siberian Large Igneous Province. It is shown that the volcanic section of the Kuznetsk Basin consists of the Lower (I and II units: TiO 2 = 1.6–1.9 wt %, Gd/Yb = 2.0–2.1) and Upper (III–VIII units: TiO 2 = 1.4–1.8 wt %, Gd/Yb = 1.7–1.9) sequences. The Mayzass sill is geochemically correlated with the Unit II basaltic andesite of the Lower Sequence, and the Syrkashev sill is geochemically akin to the Upper Sequence. The Kuznetsk traps originated from the partial melting of a Sr–Nd isotopically heterogeneous subduction-modified lithospheric mantle. They are geochemically comparable to low-Ti basalts of the low–middle Nadezhdinsky suite from the Noril’sk region, but differ in Sr–Nd isotope composition. The Sr–Nd isotope signatures of non-contaminated lavas and rocks of the Syrkashev sill (ε Nd ( T ) = (+4.6)–(+2.4), ( 87 Sr/ 86 Sr) T = 0.7047–0.7054) are inherited from the ancient lithospheric mantle and do not represent the contribution of the Siberian plume. The Mayzass sill rocks (ε Nd ( T ) = (+2.2)–(+2.1); ( 87 Sr/ 86 Sr) T = 0.7055–0.7063) are derived from a parental melt contaminated with crustal carbonates.
ISSN:1028-334X
1531-8354
DOI:10.1134/S1028334X23600263