Sedimentary response and record of circulation in the eastern China shelf seas

English Abstract:

China shelf sea are located between the edge of the Pacific Ocean and the Asian continent, as terrain great drop and big river (the Yangtze and Yellow River) development, is one of most abundant terrigenous flux sea in the Earth. The shelf circulation plays an important role in diffusion and transport of the river substances into the sea. Large clinoform sedimentary beddings found in the Yellow Sea and East China Sea in recent years are closely related to the Fujian- Zhejiang coastal current and Shandong coastal current respectively. Alongshore currents are driven by seasonal monsoon and related to sea water compensation. They are strongest in winter, weakest in summer. So far understanding of coastal current mainly from observations, modeling and remote sensing color instructions. However, in general understanding of the Chinese offshore coastal current and warm currents is still not sufficien, mainly due to lack of observational data, especially long-term continuous observation is still lacking. Sediment geochemical and mineral composition, particle size and their distribution have a good indication to the formation, evolution and the distribution of coastal current and warm current. Sediment composition of grain size, mineralogy and chemistry can effectively reflects the monsoon control on the coast current, while the monsoon changes has a periods of solar activity, sunspot activity cycles and the Southern Oscillation (ENSO) cycles. Sedimentary records can indicate Shandong coastal currents two paths. Integrated research results show that Fujian and Zhejiang alongshore current flow across the Taiwan Strait and may have been extended to the southern coastal Fujian Province. Modern sedimentation rates are much lower and contents of feldspar, mica and other light detrital minerals reduce in the outer continental shelf, whereas calcite, heavy detrital mineral content and 210Pb concentration that represent the ocean, atmosphere components and hydrodynamic, respectively, increased significantly, reflecting terrigenous supply and influence greatly reduced, while marine biological role and ocean dynamic dominant in the outer continental shelf of the East China Sea. Moreover, Ocean dynamic role strengthen from north to south in the middle and out shelf.