現世海底堆積物および堆積岩にみられる粘土鉱物組成

抄録

Mineralogical study on clay minerals was carried on about 650 samples from Recent marine sediments and sedimentary rocks. Confirmation of kinds of clay minerals and their quantitative estimation were carried by means of X-ray powder diffraction data obtained from well-oriented powder slide, which were prepared by natural specimen, those heated at every temperatures, those treated by ethylene glycol, hydrochloric acid, ammonium nitrate solution, and magnesium acetate solution.
Recent marine sediments: Montmorillonite, chlorite, illite, hydrated halloysite, and a small amount of kaolinite were found in these sediments. In shallow water sedimnts clay mineral compositions show some variation from region to region. Composition of clay minerals in shallow water sediments is found to be affected by source materials and water movements. The samples in deep-sea sediments generally have the same clay mineral composition, and no marked difference was found between successive levels in the core samples.
Tertiary sedimentary rocks: Montmorillonite, chlorite, hydrated illite, illite, kaolinite, and mixed layer mineral of montmorillonite and illite were found in these sedimentary rocks. Each locality has a characteristic clay mineral composition. In Ishikari coal-field, there is a great difference of clay mineral composition between upper and lower formation at unconformity.
Mesozoic sedimentary rocks: The specimen are composed of chlorite and illite. The relative amounts of them somewhat vary from region to region. Al-vermiculite and Al-montmorillonite were found in a weathered sample.
Palaeozoic sedimentary rocks: Clay minerals were mainly chlorite and illite. They were generally well crystallized sorts.