Kitinosuke Henmi

Chemical compositions and X-ray properties of regularly interstratif ied mica-smectites

Regularly interstratified dioctahedral mica-smectites from hydrothermally altered rocks (seven roseki deposits and a geothermal area) in Japan were examined by chemical analysis and X-ray diffractmetry. Chemical analysis shows that Si/Al ratios of the tetraherdral cations lie between 3.54 and 5.25, and the octahedral sites are occupied almost exclusively with Al3+. The expansible layers have beidellite-like compositions, but they have expansion characteristics similar to montmorillonite. Interlayer cations of mica-like layers are composed of Na+, K+ and Ca2+, and the relative amounts of the three cations vary from specimen to specimen. The basal spacing of interstratified structure increases in proportion to the K content of the non-expansible layers.