A new occurrence of basalt (minimum K/Ar age 57.9 ± 2.2 m.y.) is reported from Budaliget, near Budapest. Major and minor element concentrations show that the basalts are alkaline and potassic in nature ranging from olivine tholeiite to moderately undersaturated basanite. High mg-values and concentrations of Ni and Cr indicate that some of the samples may represent primary compositions. High pressure accidental xenoliths, xenocrysts and cognate megacrysts are frequent and the chemical zoning patterns of olivine and pyroxene phenocrysts indicate a complex evolution and polibaric conditions for the crystallization. The discovery of the new basalt occurrence is important from a geodynamical point of view: prior to the last two major geodynamical events (Plio-Pleistocene rifting with associated alkali basaltic volcanism and collision of microplates with associated Miocene calk-alkaline volcanism) the continental lithosphere below NE Transdanubia may have experienced another rifting period in the Paleocene or Upper Cretaceous.
- Alkali basalt
- K/Ar age
- chemical zoning in phenocrysts
- major and trace element geochemistry
- peridotite xenolith
ASJC Scopus subject areas
- Geochemistry and Petrology