THE ZEOLITE DEPOSITS OF GREECE

Zeolites are present in altered pyroclastic rocks at many localities i n Greece, and large deposits of potential economic interest are presen t in three areas: (1) the Evros region of the province of Thrace in th e northeastern part of the Greek mainland; (2) the islands of Kimolos and Poliegos in the western Aegean; and (3) the island of Samos in the eastern Aegean Sea. The deposits in Thrace are of Eocene-Oligocene ag e and are rich in heulandite and/or clinoptilolite. Those of Kimolos a nd Poliegos are mainly Quaternary and are rich in mordenite. Those of Samos are Miocene, and are rich in clinoptilolite and/or analcime. The deposits in Thrace are believed to have formed in an open hydrologica l system by the action of meteoric water, and those of the western Aeg ean islands in a similar way but under conditions of high heat flow, w hereas the deposits in Samos were formed in a saline-alkaline lake.