О.М. Туркина.
Анализ характера мантийных источников базитовых ассоциаций на основе геохимических и изотопных Nd-данных
Keywords: mafic rocks; trace element; isotopic composition; mantle sources
The (La/Nb)pm, (Th/La)pm, (La/Sm)pm, (NbY)pm ratios <1 in mafic rocks correspond to a depleted mantle source, while ≥1 corresponds to a undepleted/enriched source. (La/Nb)pm does not change during melting of mantle peridotites, so the Nd minimum is a characterictic feature of the lithospheric mantle metasomatized by fluid/melt. According to the isotopic Nd composition, there are two mantle sources: (1) depleted (+eNd), which corresponds to the asthenospheric and/or lithospheric mantle of restite origin, (2) enriched (-eNd) lithospheric, having decreased Sm/Nd due to metasomatism. Estimates of the character of the mantle sources of mafic rocks in terms of their trace element and isotopic composition can either correlate with each other or differ.
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