Origin of the Middle Paleoproterozoic Tiksheozero Ultramafic-Alkaline-Carbonatite Complex, NE Fennoscandian Shield: Evidence from Geochemical and Isotope Sr-Nd-Hf-Pb-Os Data
Autor: | Alexey Chistyakov, Boris Belyatsky, Maria Bogina, Evgenii Sharkov, Robert Krymsky |
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Jazyk: | angličtina |
Rok vydání: | 2021 |
Předmět: |
Sr-Nd-Hf-Pb-Os isotopes
lithosphere mantle Incompatible element 010504 meteorology & atmospheric sciences Geochemistry 010502 geochemistry & geophysics 01 natural sciences Mantle (geology) Petrography chemistry.chemical_compound ultramafic-alkaline-carbonatite complex Ultramafic rock 0105 earth and related environmental sciences geography geography.geographical_feature_category Isotope Geology Geotechnical Engineering and Engineering Geology Mineralogy Silicate Karelian Craton Craton chemistry Carbonatite QE351-399.2 Middle Paleoproterozoic |
Zdroj: | Minerals Volume 11 Issue 6 Minerals, Vol 11, Iss 570, p 570 (2021) |
ISSN: | 2075-163X |
DOI: | 10.3390/min11060570 |
Popis: | This article reports new geochemical, Sr-Nd-Hf-Pb and Re-Os data on the rocks of the Middle Paleoproterozoic (1.99 Ga) Tiksheozero ultramafic-alkaline-carbonatite complex confined to the northeastern margin of the Karelian Craton. We focus on the poorly studied silicate rocks. Based on petrographic and geochemical research, the silicate rocks are subdivided into two groups: an ultramafic-mafic series depleted in REE, and other incompatible elements and an alkaline series enriched in these elements. Isotope studies showed that all rocks have juvenile isotope signatures and were likely derived from a primitive OIB-type mantle source with possible contributions of the subcontinental lithospheric mantle (SCLM). Insignificant crustal contamination is recorded by Pb and Os isotopic compositions. The incompatible element enrichment in the alkaline rocks and depletion in ultramafic-mafic rocks of the mildly alkaline series with allowance for insignificant crustal contamination confirm their derivation from different primary melts. However, a narrow range of Sr, Nd, Hf, and Pb isotope compositions and compact clusters in 207Pb/204Pb-206Pb/204Pb, Nd-87Sr/86Sr and Hf-Nd isotope diagrams indicate their origination from a common mantle source. A model of subsequent two-stage melting is being most consistent with the geochemical data for this complex. |
Databáze: | OpenAIRE |
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