Hydrothermal behaviors of an interstratified mineral from the Mine of Ebara, Hyogo Prefecture, Japan

An example of changes from randomly interstratified clay mineral to regular one

Abstract

A radomly interstratified mineral (mica-montmorillonite) with cation-exchangeable property was found in the Mine of Ebara, near Kinosaki, Hyodo Prefecture.
Its basal spacing is 13.7Å, 12.6Å and 11.6Å in each humid, ordinary and dried air condition respectively.
The mineral changes to regular interstratified mineral (chlorite-montmorillonite) with 30Å spacing at I kb water pressure in the range from 360°C to 480°C. At temperatures over 480°C, it changes to a mica mineral.
When the starting material is used after treating with hydrochloric acid, it direcly changes to mica at 380°C and 1kb.