Clay minerals of sea muds in the Ariake Sea

Clay fractions (< 2 p) from f our muds in the Ariake Sea and one soil derived from the marine deposits in the Kojima Bay were examined by x-ray, chemical, thermal, and electron micrograph methods. Besides these analyses ethylene glycol retention and base exchange data were presented. The results obtained indicated that the clay minerals of these samples were predominantly constituted from minerals of the illite-montmorillonoid series. This montmorillonoid may be somewhat iron rich montmorillonite or some intermediate members between the montmorillonite and the nontronite. And the clay separates from the Kojima Bay showed more illitic behaviour than the one from the Ariake Sea. The striking similarity of these clay fractions examined, without regard to the locality, suggests that these clays were formed in a similar environment of the shallow sea.有明海沖積層に属する古い水田土壌の粘土は Montmorillonoid-illite系に属し, このMontmorillonoidはMontmorillonite-Nontronite系すなわち八面体層にかなり多量のFeを含む鉱物である. 本土壌の粘土はその鉱物の性質においてわが国陸生土壌の粘土とはいちじるしく趣きを異にしているもののようであり, この点は本土壌の生産力を考察するに際して看過してならないことと考える. この粘土は有明海において生成されたものと推定されるので, 広く有明海の各地から泥土を採取し, それ等の粘土鉱物の性質を数種の方法で検討した. なおこの種の粘土は有明海特有のものであるか, 或は類似の条件の海底においては同様な粘土を生成するものかについて予備的な研究を行うために児島湾干拓地の土壌についても実験を行つた