HEAVY MINERAL CHARACTERISTICS OF SURFACE SEDIMENTS IN THE SUBAQUEOUS YANGTZE RIVER DELTA

Heavy mineral characteristics of 145 surface sediment samples collected from the subaqueous Yangtze River delta were analyzed in detail. The analysis results suggested four mineral provinces in the study area. They were south part of delta front (area I), north part of delta front (area Ⅱ), delta front (area Ⅲ) and south part of front delta (area IV), each of which indicated unique sedimentary process, sedimentary environment, and weathering condition. In general, heavy minerals of the Yangtze River delta were characterized by relatively high contents of muscovite and sericite derived from metamorphic rock, and were dominated by common hornblende and epidote assemblage. At some places in the study area, augite and Fe-oxide mineral were found with low contents. According to present research, heavy minerals compositions of silty sand and sandy silt were relatively steady, indicating that heavy minerals of these two sediment types could imply sediment from the subaqueous Yangtze River delta when we do sediment source researches on the continent shelf of the East China Sea.