Original paper

Volcanism on Anafi island: short living, extensional, hydromagmatic volcanism in the central part of the South Aegean volcanic chain (Greece)

Leichmann, Jaromir; Hejl, Ewald

Abstract

New field observation and petrological data certify the existence of Neogene or Pleistocene volcanism on the island of Anafi in the southern Aegean sea, and complete the knowledge of the South Aegean volcanic chain. They rule out the enigmatic position of Anafi, which was supposed to be the only non-volcanic island in the centre of the Quaternary active volcanic arc. Volcanism on Anafi was rhyolitic; both intrusive and extrusive types occur on the island. Volcanic activity was related to an extensional basin, which became filled with variegated siliciclastic sediments and to a lesser extent by volcanogenic deposits. Tectonic extension and deep circulation of meteoric waters have triggered a predominantly phreatomagmatic to phreatic volcanism. Abundant water supply gave rise to a pervasive argillic and carbonatic alteration of both volcanic and their country rocks. A subsequent compressional stage terminated the volcanic activity and prevented the formation of a larger volcano. The strong alteration of Anafi's volcanic rocks is unfavorable for radiometric dating, but the age of volcanic activity can be deduced from the finding of tuff layers within the Theologos fm., which is controversially classified as Neogene or Plio-Pleistocene.

Keywords

aegeanvolcanismalterationstable isotopesstrontium isotopes