Preliminary investigations were carried out for the determination of clay mineralogy of the Sundarban soils. A total of 50 pedons were examined over a north-west to south-east transect running through the Sundarbans. Finally, four pedons were selected for laboratory investigation.
Based on the observations made from the field investigations, as well as from the results of the physicochemical analyses, it appeared that pedologically the soils were very young and possessed no diagnostic horizon.
The dominant minerals in the clay fraction are weathered mica and smectite with traces of kaolinite, chlorite and interstratified minerals. The clay minerals were identified mainly by the X-ray diffraction technique supported by other techniques. It was observed that, so far as the clay mineralogical composition was concerned,the Sundarban soils had a homogeneity both in vertical and in horizontal directions. Slight variation in the clay mineralogical composition and content occurring among the pedons are the inherited properties of the soil materials.