福岡県津屋崎産沸石鉱物の化学組成と成因

抄録

In Tsuyazaki area, Fukuoka Prefecture, there spread Cretaceous granodiorites and Tertiary sediments, in which many kinds of zeolites occur as the veinlets with quartz or calcite and as the cementing materials of conglomerate. These zeolites were identified as heulandite, laumontite, leonhardite, stilbite and analcime by X-ray diffraction, and their chemical compositions were obtained by electron probe micro-analyser. Heulandite has a composition of Ca_{0 65} Na_{4 70} K_{0 74} Mg_{0 08} Al₈₂₅ Si_{28 09} O₇₂ · 22.87H₂O and occurs as the cementing material of conglomerate. Stilbite has a composition of Ca_{1 9} Na_{6 16} K_{0 58} Mg_{0 04} Al_{9 74} Si_{26 03} O₇₂· 27.47H₂O and often occurs on the heulandite crystal. Leonhardite has a composition of Ca_{3 41} K_{0 42} Mg_{0 01} Al_{7 74} Si_{16 38} O₄₈·13.96H₂O and occurs as the veinlets with quartz. Analcime has a composition of Na_{0 94} Ca_{0 03} Al_{0 98} Si_{2 02} O₆ 0.99H₂O and occurs as an idiomorphic crystal in the vug of sandstone in association with a petrified wood. Judging from their occurrences, it is thought that the zeolites found in Tsuyazaki area were formed by the hydrothermal process.