CLAY MIMERALS DISTRIBUTION PATTERN IN SURFACE SEDIMENTS OF WESTERN BOHAI AND THEIR PROVENANCE IMPLICATIONS

Clay mineralogy was studied for the 45 surface sediment samples taken from the Western Bohai Sea. Data shows that the spatial distribution of the clay is clearly provenance dependant. The clay minerals of the studied area are dominated by illite, which varies from 43.1%~74.6%, followed by montmorillonite, which changes from 5.2%~48.4%. The content of kaolinite (2.7%~9.9%) and chlorite(3.0%~12.0%) are rather low. In terms of clay mineral assemblages, the type(Ⅰ) consisting of illite, smectite, kaolinite and chlorite dominates, and followed by the type (Ⅱ) consisting of illite, smectite, chlorite and kaolinite. The clay minerals in the region is terrestrial with the Yellow River, Haihe River, Luanhe River and others as sources. According to the sources, the studied area can be divided into 3 source regions, namely the Haihe River- Yellow River and Luanhe River source region; the northern region; and the Yellow River sources region in the southeast. In addition to sources, the circulation of Bohai Sea is also critical to the distribution of clay minerals.