Abstract:Chlorite in the sedimentary rocks from Mt. Tobigamori, Iwate Prefecture, Japan altered to minerals (14 Å minerals) having a strong X-ray reflection at 14 Å under weathering condition. The 14 Å mineral...Chlorite in the sedimentary rocks from Mt. Tobigamori, Iwate Prefecture, Japan altered to minerals (14 Å minerals) having a strong X-ray reflection at 14 Å under weathering condition. The 14 Å minerals are the intermediate state from chlorite to vermiculite, and consist of chlorite-like layers and vermiculitelike layers. The structural chemical properties of vermiculitelike layers are slightly different from sample to sample. In one sample the vermiculite layer in the 14 Å mineral shows a behaviour similar to an aluminum interlayered vermiculite by K+ treatment. In the second sample it is similar to an calcium interlayered vemiculite on organic treatment. In another samle the 14 Å mineral changes in its properties with its particle size. Chemical compositions of the bulk samples reflect such properties of 14 Å mineral contained in them. Amount of vermiculite-like layers in these 14 Å minerals is estimated at 50-60% from the X-ray diffraction analysis.Read More