The clay mineralogy of three red soil profiles (Typic Hapludalfs) developed on Rajmahal Trap of Bihar was studied using chemical data. X-ray diffractograms and DTA curves. The surface soils in profile 1 contain mica, kaolinite and smectite infair amounts, while profile 2 indicates the occurrence of kaolinite, mica and smectite with small amount of vermiculite followed by mica-smectite intergrade. The surface soils of profile 3 exhibit only kaolinite and mica as dominant minerals. Fairly high steepness in the site of profile 3 could have been the reasonfor removal of bases. Higher values of CEC even in profile 3 might have also been because of amorphous materials as evident from chemical data.
Rajmahal trap, red soils, clay minerals
