THE TYPE OF QUATERNARY SEQUENCE IN THE EAST CHINA COASTAL PLAIN

Based on materials from the drilling holes in the west coast of Bohai Bay and the Yangtze River delta area, the present paper determined two types of sequence stratigraphy in the East China coastal plain formed under the tectonic subsidence setting. The great flooding events which had a cycle of over 0.10 Ma in the fluvial system and occurred at cir. 2.60 Ma, 0.8 Ma, 0.5 Ma (?) and 0.15 Ma respectively, could be correlated to the transgressive system tract(TST)in the sequence stratigraphy. These are related to the periodic uplifting of northern mountain in the North China basin in the north of Tianjin and to that of low mountain and hills along the Yangtze River, and all represent the response of environment in the coastal plain to the tecto-climatic cycles in West China. Since MIS5 three transgressions with 10 ka period controlled by global sea-level change occurred in East China coastal plain. Combining with research results in the sea region, it can be determined that a complete transgression-regression sequence appeared in MIS1 period; in the coastal plain the Holocene transgression bed formed since 10 ka is corresponding to the parasequence in the high-stand tract (HST). The basal peat dated 7~10 ka is the maximum flooding surface and the peat older than 10 ka in ¹⁴C age could be found at the incised valley.