Ultrapotassic pliocene-quaternary volcanism in the region of bar (Pannonian basin): New evidence and geodynamic implications

New data on the chemical composition of ultrapotassic Bar volcanics penetrated by the Bar-6 well are presented. The mineral compositions are analyzed, and lamproitic affinity of volcanics is established. According to the new K-Ar datings, the volcanics are not older than 2 Ma. Comparative analysis of Bar volcanic rocks against the ultrapotassic formations of Vardar zone in Macedonia and in other regions showed that Bar volcanics form the northernmost edge of the zone of ultrapotassic Pliocene-Quaternary volcanism extending up to southern Macedonia. This zone was formed in conditions of extension, and the volcanism itself was a result of the melting of the depleted mantle.