1044 / 2024-09-20 09:49:45

Characterization of grain size and clay mineral distribution and provenance implication of surface sediments in Tangshan Harbor, Bohai Bay

sediments; grain size; clay minerals; river; provenance; Bohai Bay

Session 10 - The biogeochemistry of trace metals in a changing ocean

161 surface sediments from the Tangshan Harbor, Bohai Bay were analyzed for grain size and clay composition and distribution to explore the sources of sediment and their controlling factors. The results show that the average grain size (Mz)Φ of surface sediments in Tangshan Harbor ranges from 1.4 to 7.7, and mainly consists of silty sand, sandy silt, and a small amount of sand and clay. According to the characteristics of grain size parameters and end-element model analysis, the sediments can be divided into three zones and four end-elements from EM1 to EM4: the northeastern part of the area is dominated by EM3 end-element sand and chalky sand, with poor sorting, positive skew, and strong dynamics of depositional environments; the central Caofeidian Deep Trough area is dominated by EM4 end-element sandy chalk and chalky sand, with poor sorting, positive skew, and strong dynamics of depositional environments; and the southern part and the Tangshan Harbor area is dominated by EM1 and EM2 end-element chalk, with moderate to poor sorting and weak depositional dynamics. The clay minerals are relatively high in illite (72%), smectite (12%) followed by chlorite (8%) and kaolinite (8%). The provenance analysis shows that the source of surface sediments in Tangshan Harbor is mainly the detrital material mixed Yellow River and Haihe River, while the northeastern part of the study area and the Caofeidian Deep Trough may have some coarse-grained material from the ancient Luanhe Delta. The Bohai Sea circulation and tidal currents control the transport of fine-grained sediments mainly to the south and near Tangshan harbor, while coarse-grained materials are transported and deposited to the northeastern and central Caofeidian area.