High-resolution sequence stratigraphy of the Holocene strata on the East China Sea shelf

The high-resolution sequence stratigraphic division and correlation of the Holocene strata on the East China Sea shall are made on the sequence stratigraphic theory dnd¹⁴C dating, litho-, bio-, chemo-, isotopic-, weather-, and magneto-stratigraphy, in conjunction with sedimentological analysis of typical boreholes in different sedimentary settings,result-ing in the construction of the sequence stratigraphic framework and sea-level curves and associated sequence stratigraphic model. The Holocene strata on the East China Sea shelf, which correspond to a sixth-order (1-10ka) sequence, may be divided into three seventh-order (0.1-1 ka)sequences and many lower-order sequences, representing one sixth-order or three seventh-order cycles of relative sea-level changes influenced by lower-order sea-level fluctuations. The seventh-order sequences exhibit internal architectures and genetic framework similar to those of third-order sequences. During the sedimentary evolution of the East China Sea shelf in the Holocene, the Yangtze River (delta) once extended at least for three times through the East China Sea shelf into the Okinawa Trough, and brought about three beds of transgressive reworked "eluvial sand" sediments. During the Holocene, the maximum sea level in the East China Sea occurred between 6 and 5 ka B.P., 2 to 4m higher than the present-day sea level;the minimum sea level appeared about 10ka B. P., 130 m lower than the present-day sea-level. Moreover the sea level is still rising with a small margin because of the "greenhouse" effects. The fact is that sequence stratigraphy has contribute a lot to the refinement of oceanic sedimentology and better resolution of un-resolved problems in oceanic sedimentology.