HEAVY MINERAL PROVINCES OF THE SURFACE SEDIMENTS IN CENTRAL-SOUTHERN EAST CHINA SEA AND IMPLICATIONS FOR PROVENANCE

More than 40 species of heavy minerals and a small amount of lithic and weathered fragments are found in the surface sediments of the middle-southern East China Sea.Sediment sources, depositional environments and the main controlling factors were analyzed and discussed. High percentages of opaque heavy minerals mainly occur on the outer shelf of the East China Sea at water depth deeper than 100 m, while the content of opaque heavy minerals in the Zhejiang-Fujian coastal areas is very low. The content of stable heavy minerals depends upon the distance to the coast, and from the inner to the outer shelf, the content gradually increases. Micas and authigenic pyrite are found concentrated in the inner shelf of Zhejiang-Fujian coastal areas, indicating a rather weak hydrodynamic condition and reducing environment. Cluster analysis suggests that the study area can be roughly divided into two zones. The zone I includes the Zhejiang-Fujian coastal areas and the central and western Taiwan Strait with water depth less than 60 m. The sediments are mainly transported by the southward coastal currents. The zone II mainly includes the middle and outer continental shelf, continental slope and part of the Okinawa Trough in the East China Sea with water depth deeper than 80 m. The sediments are mainly derived from the East Asian continent during the low sea level period of Late Pleistocene.