Geology and geochemistry of the Eocene zeolite-bearing volcaniclastic sediments of Metaxades, Thrace, Greece

• Autores: Th. Koutles
• Localización: Estudios geológicos, ISSN 0367-0449, Vol. 51, Nº 1-2, 1995, págs. 19-28
• Idioma: inglés
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• Resumen

  • The Eocene zeolite-bearing volcaniclastic sediments (Ca-rich clinoptilolite 5 1 % on average) of Metaxades, Thrace, Greece, are studied in terms of geology and chemical composition. The alternating formations along a vertical profile in the Metaxades main quarry face are: Discrete horizons of zeolite-bearing volcaniclastic tuffs, zeolite-bearing volcaniclastic tuffs including pebbles, zeolite-bearing volcaniclastic tuffs including thin silica-rich layers, and a calc-clayey horizon. A positive correlation is observed between MgO and CaO in the volcaniclastic tuffs including silica-rich layers. Sr, Rb and Ba are the most abundant trace elements in all layers; among them, Sr is found to correlate positively with zeolite. The enrichment of some trace elements is mainly attributed to mineral abundances, mineral chemistry or leaching processes. The zeolite-bearing volcaniclastic sediments of Metaxades represent an inhomogeneous sequence, which was deposited in a shallow marine environment under turbulent to quiet sedimentary conditions