Abstract
In the Izu Peninsula, central Japan, seventeen species of zeolites mainly occur in volcanic rocks and volcaniclastic sediments of Miocece to Pleistocene in age. Pervasive zeolites are wairakite, laumontite, heulandite, stilbite, and chabazite and minor are yugawaralite, scolecite, epistilbite. They occur in veins, fractures and druses and are zonally distributed in hydrothermal alteration zones trending NW-SE and NE-SW.
Na-zeolites such as clinoptilolite, mordenite, analcime and ferrierite mainly replace vitric materials in volcaniclastic sediments. They were probably formed by thermal effects of magma which intruded at very shallow places during Pliocene to Pleistocene age.
There are few localities of fibrous zeolites such as natrolite, mesolite, and thomsollite.
