The pliocene volcanism of the voras Mts (Central Macedonia, Greece)

Major element chemistry, K/Ar ages and trace element data are reported for volcanic rocks from the Voras volcanic complex of Central Macedonia (Greece). Petrological data show that the Voras volcanic rocks consist essentially of intermediate members of the high-K calc-alkaline and shoshonitic series, the most abundant rock types being high-K andesites and dacites, latites and trachytes. K/Ar ages determined on selected samples show values ranging between 5.0 and 1.8 m.y., indicating that the Voras volcanism was active from Pliocene up to the Lower Pleistocene. The high Th, Hf, Ba and LREE shown by some representative samples together with their strongly fractionated light and heavy REE patterns and the absence of significant negative Eu anomalies indicate a magma genesis by low degrees of partial melting of a source enriched in large ion lithophile elements, leaving a garnet-bearing and plagioclase-free residue. This source is believed to be represented by a mantle garnet peridotite enriched in incompatible elements.