Clay Mineralogy of the Soils of Indrayani River Basin, Western Maharashtra, India

Clay mineralogy of the soils of Indrayani river basin of western Maharashtra, has been investigated with the help of DTA, XRD and IR spectroscopic techniques. On the basis of clay mineral assemblage of the soils, trends of chemical weathering of basalt and formation and evolution of the soils have been visualised. It has been observed that the chemical weathering of basalt of nearly uniform chemical and mineralogical composition, has led to the development of two contrasting soil types. Red to reddish-brown coloured lateritic to semi-lateritic soils of the western part of the basin are predominated by the presence of kaolinite group of clay minerals. Formation of these soils has been attributed to free drainage and high rainfall conditions. On the other hand, grayish-black coloured margalithic or black cotton soils showing predominance of the minerals of smectite group, have been formed under poor or restricted drainage and low rainfall conditions in the eastern part of the Indrayani river basin. An attempt has been made to discuss the formation and evolution of soils in the light of clay mineralogical data.