Petrology and Geochemistry of Peridotite Xenoliths in Alkali Basalts from the Transdanubian Volcanic Region, West Hungary

Abstract

Type I (Cr-diopside group) peridotite xenoliths occur abundantly at four volcanic vents (Szentbékálla, Szigliget, Bondoró-hegy, Gérce) in the Transdanubian Volcanic Region of Hungary (TVR). They comprise four-phase spinel Iherzolites and spinel harzburgites. The only additional phase a brown amphibole in some of the nodules from Szigliget. Protogranular and equigranular textures prevail except at Gèrce where porphyroclastic textures predominate. Attention has been focused however, on a rarer textural type displaying spherical, subhedral, or rarely even euhedral spinel inclusions in silicate phases (special group xenoliths).