摘要
The clay mineral composition of surface sediments from the middle reach of Huaihe River drainage area was analyzed with the X-ray diffraction method. The results show that illite, averaging 52.3%, is the dominant clay mineral, followed by kaolinite (17.0%), smectite (16.8%), and chlorite (13.9%). The sediments from the Huaihe River are characterized by high contents of smectite and kaolinite compared with those from the Yellow and Yangtze Rivers. The sediments from the middle reach of the Huaihe River can be easily distinguished from the Yellow river and Yangtze River sediments in the triangular diagram with illite, smectite and Kaolinite+chlorite as end members. In general, weathering intensity, which is mainly controlled by lithology, climate, and morphology, determines the formation of clay minerals.