Tertiary to Quaternary evolution of volcanism in the Aegean region

Abstract

Summary Widespread orogenic volcanic activity has continued in the Aegean area from the Oligocene to present. Two main phases of activity are recognized. One developed in the North Aegean area from Oligocene to Middle Miocene times and a second started in the Pliocene, building the active South Aegean volcanic arc. Between these two phases, Upper Miocene to Quaternary volcanism of variable petrogenetic affinity occurred to a limited extent, essentially on the margins of the Aegean microplate. The products erupted during the Oligo-Miocene phase consist mainly of calc-alkaline and shoshonitic intermediate lavas and pyroclastics with minor acidic and basic rock types. The volcanic activity started in the northernmost part of the North Aegean area with mostly calc-alkaline intermediate and acidic volcanics. The volcanism shifted successively southwards becoming progressively enriched in potassium. This evolution is interpreted as being related to an increase in the dip of the Benioff zone under the Eurasian plate, resulting from a reduction in the plate convergence rate after continental collision. The volcanic products of the active south Aegean arc are mainly andesites with minor basalts and rhyolites which display the chemical character typical of calc-alkaline series erupted on thin continental margins. The South Aegean arc is believed to be the surface expression of active subduction of the African plate. Scattered Upper Miocene to Quaternary activity is interpreted as occurring in zones of tensional strain along the borders of the Aegean microplate.

Kinematic reconstructions and magmatic evolution illuminating crustal and mantle dynamics of the eastern Mediterranean region since the late Cretaceous

“…44 Berza et al, 1998], the Eocene calc-alkaline magmatic province (figures 8j-n) [Harris et al, 1994; and the still active south Aegean volcanism (figures 8x-y) [Fytikas et al, 1984;Pe-Piper and Piper, 2005]. In reconstructed cross-sections (figures 9 and 10), all these magmatic provinces are emplaced above a dehydrating oceanic slab (i.e.…”

“…This typical arc-related volcanism mostly has a medium-K calc-alkaline composition [Fytikas et al, 1984;Pe-Piper and Piper, 2005;Ersoy and Palmer, 2013].…”

Rayleigh wave group velocity tomography in the Aegean area

“…Fleischer, 1964;Vogt and Higgs, 1969;Makris, 1976), high heat flow (e.g. Fytikas et al, 1985) and high attenuation of seismic energy (e.g. Papazachos and Comninakis, 1971;Hashida et al, 1988).…”

Mineralogical and Geochemical Characterization of the Olympias Mine Tailings, Ne Chalkidiki, Greece

“…Regarding the igneous activity, the region of NE Chalkidiki is characterized by a post-orogenic acid magmatism with intrusions of porphyry calc-alkaline to shosonitic igneous rocks in SMM during Tertiary (Kockel et al, 1975;Kockel et al, 1977;Fytikas et al, 1984;Tompouloglou et al, 1986;Gilg and Frei, 1994). In the Kassandra mining district, three major Tertiary magmatic rocks have been distinguished by Gilg and Frei (1994); the Stratoni granodiorite (27.9 ±1.2 Ma, U/Pb on zircons), the phyllically altered granodioritic to quartz-dioritic porphyry dikes and stocks (minimum age span of 25.4 ±0.6 to 24.4 ±0.6 Ma, biotite K/Ar) between Fisoka and Aspra Chomata, including Skouries porphyry, and the latest andesite porphyry dikes (19.1 ±0.6, K/Ar biotite-whole rock isochrones) at Stratoni region.…”