Stratigraphic framework and evolution of the mid─late Quaternary (since marine isotope stage 8) deposits on the outer shelf of the East China Sea

摘要: Abstract The East China Sea (ECS) is a vast river-dominated depositional basin because of its broad shelf and extensive river sediment supply. This study investigated the mid–late Quaternary stratigraphic framework evolution outer ECS based on borehole core (DH02) seismic profiles. Seven sedimentary facies were recognized in sediments according to lithology, grain-size composition, structure, microfossil assemblages, while eight unconformity-bounded major units identified Based seismic–core correlations, dating data (radiocarbon optically stimulated luminescence), comparison between cycles sea-level curves, 100 m thick strata below seafloor divided into three sequences corresponding glacial–interglacial marine isotope stage (MIS) 1–2, MIS 3–6, 7–8 (Sq1–Sq3 from top bottom). In particular, Sq1 developing present highstand consists mainly deposits transgressive systems tract (TST), including tide-influenced river, tidal flat, tide-dominated estuarine facies. Sq2 Sq3 consist prodelta related inner-shelf forced regressive (FRST) similar those Sq1. For all sequences, thin-sand sheet layer open-shelf represents (HST). Deposits lowstand (LST) typically represented by addition, comprehensive analyses seabed sand ridge distribution, characteristics, deposition mechanism suggest that occurrence paleoestuary with transgression determined development field. these results, conceptual sequence model association LST, TST, HST, FRST was constructed. Overall, our framework, along stratigraphy other shelves, suggested fluctuations, huge amounts supply, active subsidence, gentle topography, erosion processes (transgression regression) controlled shelf.