Clinopyroxene with diverse origins in alkaline basalts from the western Pannonian Basin: implications from trace element characteristics

Jankovics, M Éva [Jankovics, M. Éva (kőzettan-geokémia), szerző] MTA-ELTE Vulkanológiai kutatócsoport (ELTE / TTK / Ft_K); Taracsák, Zoltán; Dobosi, Gábor [Dobosi, Gábor (Geokémia), szerző]; Embey-Isztin, Antal [Embey-Isztin, Antal (Kőzettan-geokémia), szerző] Magyar Természettudományi Múzeum; Batki, Anikó [Batki, Anikó (magmás-kőzettan g...), szerző] MTA-ELTE Vulkanológiai kutatócsoport (ELTE / TTK / Ft_K); Harangi, Szabolcs [Harangi, Szabolcs (Magmás geokémia), szerző] Kőzettan-Geokémiai Tanszék (ELTE / TTK / Ft_K); Hauzenberger, Christoph A

Angol nyelvű Tudományos Szakcikk (Folyóiratcikk)
Megjelent: LITHOS 0024-4937 262 pp. 120-134 2016
  • SJR Scopus - Geochemistry and Petrology: D1
    Abstract Clinopyroxene crystals of various origins occur in the unusually crystal- and xenolith-rich alkaline basalts of the Bondoró-hegy and the Füzes-tó scoria cone, which are the youngest eruptive centres in the Bakony-Balaton Highland Volcanic Field, western Pannonian Basin. The clinopyroxenes show diverse textural and zoning features as well as highly variable major and trace element chemistry. Xenocryst, megacryst and phenocryst crystal populations can be distinguished on the basis of their compositional differences. The trace element patterns of green clinopyroxene cores display a large range in composition and indicate that most of them have a metamorphic origin. Most of them were incorporated from lower crustal mafic granulite wall rocks, whilst only a few of them are of magmatic origin representing pyroxenite (Type II) cumulates. The colourless clinopyroxene xenocrysts reflect the texturally and geochemically diverse nature of the subcontinental lithospheric mantle beneath the studied area, mainly representing regions characterized by various stages of metasomatism. The colourless and green megacrysts are genetically related to each other, having crystallised as early and late crystallisation products, respectively, from petrogenetically related melts as part of a fractional crystallisation sequence. These melts represent earlier alkaline basaltic magmas (as represented by the Type II xenoliths), having stalled and crystallised near the crust-mantle boundary in the uppermost part of the mantle. This serves as evidence that the deep magmatic systems beneath monogenetic volcanic fields are complex, involving several phases of melt generation, accumulation and fractionation at variable depths. We show that in situ trace element analysis is necessary in order to unravel the origins and relationships of the diverse clinopyroxene populations. Such studies significantly contribute to our understanding of the ascent histories of alkaline basaltic magmas as well as provide information about the characteristics of the rocks which constitute the lithosphere. Additionally, the abundance of foreign crystals incorporated in the ascending basaltic magmas, and their potential for contamination of the host magma, must be taken into account when whole-rock geochemical data are interpreted.
    Hivatkozás stílusok: IEEEACMAPAChicagoHarvardCSLMásolásNyomtatás
    2021-03-03 19:32