The possibility of reaction between acetic anhydride and ground halloysite was studied; 100g of halloysite was ground with 300ml of acetic anhydride in a Hyswing ball mill. The reaction products were examined by the X-ray diffraction techniqe, DTA and infrared spectroscopy.
The DTA curves and the infrared spectra of the reaction products indicated that the reaction between acetic anhydride and ground powder of halloysite did occur, whereas, the same reaction did not occur between the original halloysite and acetic anhydride at a room temperature for 24 hours with frequent agitation. The strong absorptions of carboxyl group (COO^-) due to it's antisymmetrical and symmetrical vibrations were observed at 1580cm^-1 and 1420 cm^-1, respectively.
It is probable that many reactive OH groups were exposed on the surface of halloysite crystals by grinding and then acetic anhydride reacted with these OH groups. The formation of ionic bonding between the carboxylate groups and the aluminium ions (Al⁺), which were exposed on the surface of halloysite cristals by grinding, was suggested from the results of infrared spectra on the ground products.

抄録全体を表示

The weathering processes of minerals contained in decayed andesitic breccia sampled near the Horomi pass of Sapporo city were studied. Analytical technigue, was such as microscopic obsorvation. X-ray diflraction and electron microscopic observation.
The results were as follows.
1. In early stage of weathering process, Al-vermicullite rich in aluminun is formed from chrolite occured in decayed andesite. At the same time, plagioclase begins begins to alter to holloysite through albite.
2. In top horizon, regarded as most proceeded in soil formation, Al-vemicullite and kaoline minerals are found easily, along with some illite, halloysite and illite-montmorillonite mixlayered minerals.
3. Fabric and Organization of original rock are recognized only in lower horizons.

抄録全体を表示

Two kinds of glauconite grains, one (G-A) in the recent marine sediment off the coast of Nomo Peninsula and the other (G-B) in the Paleogene Saburaishi formation, have been investigated by means of x-ray diffraction method, differential thermal analysis and chemical analysis. Both glauconite grains have been found to consist essentially of randomly interstratified mica and montmorillonite; these minerals are glauconite sensu lato. G-A contains from 45 to 85 per cent montmorillonite layers and its fine grain part is rather rich in montmorillonite layers. G-B also contains 20 per cent montmorillonite layers. Chemical formulae of the glauconites are as follows:
G-A-2 (50 per cent montmorillonite layers)
(K_0.41Na_0.171/2Ca_0.02) _0.60 (Fe³⁺_0.93Al_0.59Mg_0.58Fe²⁺_0.07) _2.17 (Si_3.55Al_0.45) _4.00O₁₀ (OH) ₂
G-B (20 per cent montmorillonite layers)
K_0.59Na_0.271/2Ca_{0.02 0.88} (Al_0.86Fe³⁺_0.76Mg_0.30Fe²⁺_0.08) _2.00 (Si_3.50Al_0.50) _4.00O₁₀ (OH) ₂
In relation to the degree of crystallinity, proportion of montmorillonite layers, microscopictexture and associated minerals, the genesis of glauconite has been discussed.

抄録全体を表示