Most 14C ages on the East China Sea Shelf during the postglacial transgression are not reliable. At present, to provide a precise sea level history is still impossible. However, a rough sea level change in the last 13,000 yr based on a few valid data still can be proposed. The 5.5 m thick deposits on Qingfeng section in a big pit, 13 km east of Jianhu city, Jiangsu Province (Fig. 3), is just close to the postglacial transgression maximum and this
PIK-90 site was in tidal flat environment of a lagoon for a long history in Holocene (Zhao et al., 1996, Xue, 2002 and Xue et al., 2010). Some shells of Sinonovacula constricta with two joined valves together in original living positions were buried by deposits ( Zhao et al., 1996). They indicated that the former sedimentary environments were calm and many mollusk shells may be autochthonous. In addition, some shells of uniquely intertidal species: Cyclina sinensis, Libitina japonica and Tympanotomus cynqulata were found from the tidal flat deposits in
nondisjunction section ( Zhao et al., 1996). The shells collected from the tidal flat deposits can provide relatively reliable 14C ages even measured by LSC (liquid scintillation counting). The elevation of middle of the 3.25 m thick tidal flat deposits in this section is about at present sea level, indicating a stable tectonic setting in Holocene. The layers in this section provide reliable former sea levels and relatively reliable 14C ages in last 7700 yr ( Table 5; Fig. 7).
