Abstract
In connection to the investigation to throw light on the empirical fact that sea muds are more excellent than upland soils as the material of the ground of “Ryuka” salt field, we conducted the mineralogical survey on clay fractions separated from salt field soils and sea muds around the Inland Sea of Seto in comparison with the clay fraction separated from upland soil of Mikatagahara by carrying on the differential thermal analysis, the X-ray analysis, the chemical analysis, the cation exchange capacity measurement and the ethylenglycol absorption measurement with the samples. The results obtained are as follows.
(1) The chief difference between upland soil clay and salt field soil clay as well as sea mud clay is that the clay mineral of the former is halloysite but the latter contains three layer lattice mineral, illite or chlorite, besides halloysite.
(2) The salt field soil clay in Kagawa prefecture and the sea mud clay in the Matsunaga bay (Hiroshima prefecture) consist of hydrated halloysite, halloysite and illite, on the other hand both the salt field soil clay and the sea mud clay in Tokushima prefecture consist of chlorite and illite mixed with hydrated halloysite and halloysite.
(3) From the above result it is suggested that the mineralogical composition of the salt field soil clay and sea mud clay has close connection to their parent rock rather than their environmental condition.
