Compositional variations of mordenite from Polyegos island, Greece: Na-Ca and K-rich mordenite
Kitsopoulos, Konstantinos P.; Dunham, Ansel C.
European Journal of Mineralogy Volume 10 Number 3 (1998), p. 569 - 578
published: Jun 22, 1998
manuscript accepted: Jan 7, 1998
manuscript received: Jul 17, 1996
ArtNo. ESP147051003015, Price: 29.00 €
Abstract Mordenite dominates the mineralogy of the northwestern exposures of the Pliocene pyroclastics from Polyegos island. South Aegean Sea Volcanic Arc, Greece. Heulandite type 3 (clinoptilolite), illite, more rarely illite/smectite, opal-CT, feldspar, quartz, kaolinite and halite have been found with mordenite. Over sixty, non-recalculated, original mordenite analyses have been obtained using electron microprobe. The analyses revealed two distinct compositional types of mordenite: a typical mordenite, where Na and Ca are the main cations, and a K-rich mordenite. These two types probably reflect the nature and the chemical composition of the materials which acted as precursors for the mordenite formation. The Na-Ca mordenite had mainly as precursors any Na,Ca-rich heulandite phases initially present, and secondly some illite/smectite and a gel-like material. The K-rich mordenite had as a precursor the heulandite type 3 (clinoptilolite).