DISTRIBUTION OF HEAVY MINERAL ASSEMBLAGES IN SUBSURFACE SEDIMENTS OF DALIAN BAY AND THEIR IMPLICATIONS FOR PROVENANCE AND ENVIRONMENT

The heavy mineral assemblages and their distribution pattern of the subsurface sediments of the Dalian Bay were preliminarily discussed in this paper in connection with their sources and depositional environments as well as dominant factors. A total of 29 species of heavy mineral were discovered in the study area, dominated by hornblende and followed by epidote and ilmenite. Using heavy mineral characteristic indexes (ATi, GZi, ZTR and UM/SM), and the ratio of stable and unstable mineral as means, we divided the study area into 3 subregions, corresponding to 3 sedimentary environments. In the subregion of shallow water in the north, where dynamic sorting dominated, sediments were mainly derived from the coastal erosion of the Liaodong Peninsula. In the subregion of Central platform, where hydrodynamics was weak and differentiation dominated the distribution of heavy minerals, sediments were from the east of the study area through a long distance of transportation. In the subregion of deep water in the south, where the distribution of heavy minerals were affected by a multiple factors, including source, differentiation and sedimentary environment, the deposition of sediments was supposed to be related to the sediment resuspension driven by strong tidal current.