Cenozoic Volcanic activity in Greece

The present paper is a brief review of Cenozoic volcanism in Greece, as revealed by the last 40 years of research activity, mostly undertaken through collaboration between Italian and Greek researchers. Fabrizio Innocenti was one of the main contributors to these studies, which led to a substantial understanding of Greek magmatism and its relationship to the geodynamics of the Aegean region. Extensive volcanic activity took place in Greece during the Cenozoic period. Activity started in the North, in East Macedonia and Thrace, in the Late Eocene and gradually migrated southward, as revealed by present-day volcanic activity at Santorini. Based on geographic, radiometric and petrochemical data, the Cenozoic igneous rocks of Greece are divided into eight groups (two plutonic and six volcanic provinces). They show a large compositional variation, ranging from clearly K-alkaline (e.g., Patmos Island, Voras) and Na-alkaline (e.g., in Kaloyeri Islet) to shoshonitic, up to calc-alkaline and arc-tholeiitic (in the Santorini Volcano). The trace element and isotopic characteristics of most of the rocks indicate a subduction-related character, but some alkaline (Na-K) magmas have an intraplate character. The generation of subduction-related magmas is affected by the interplay of many factors, including the nature of the mantle wedge before metasomatism and the amount and/or composition of the subducted sediments. The presence of alkaline magmas with intraplate geochemical characteristics is due to Aegean extension, which determines sub-slab asthenosphere upwelling and the opening of slab windows. Mixing between an unmetasomatised asthenospheric mantle source and a continental lithospheric source seems to be involved in the genesis of the Na-K-alkaline magma with an intermediate character between that of intraplate and subductionrelated magmas.