CHLORITIC CLAY MINERALS IN TUFFACEOUS SANDSTONE OF THE MIOCENE GREEN TUFF FORMATION, YAMANAKA DISTRICT, ISHIKAWA PREFECTURE, JAPAN

Chloritic clay minerals occur widely in the Miocene tuffaceous sandstone, associated with laumontite, prehnite and epidote. The chloritic minerals are divided into four zones on the basis of the mineral assemblages as follows; Corrensite Zone, Transitional Zone, Swelling chlorite Zone and Chlorite Zone. Mineralogical properties of interstratified chlorite-saponite (corrensite) do not vary with horizon. Chlorite was formed from the interstratified mineral through swelling chlorite by hydrothermal alteration. Mineralogical and petrological data of these chloritic clay minerals are given in this paper.