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Sedimentary records from the inner-shelf of the East China Sea (ECS) are unique for the reconstruction of post-glacial palaeoclimate and sea-level changes. So far, the chronology of sediment succession from this region has mainly been based on radiocarbon dating, which might be problematic due to reworked deposition or old carbon contamination. In this study we tested the applicability of optically stimulated luminescence (OSL) dating to a drilling core (ECS-DZ1) taken from the northern ESC. A total of 20 OSL samples and two radiocarbon samples were collected from the upper 58 m of this core. The results indicate the likely sufficient reset of OSL signal of fine-grained (4–11 μm) quartz before burial, and thus reliable chronology for the studied core sediments. For one sample, however, the extracted coarse-grained (100–200 μm) quartz overestimated the deposition age significantly, presumably resulting from partial bleaching prior to deposition. The fine-grained quartz ages are generally consistent with the stratigraphical order, and the reliability of these OSL ages are further validated by two selective robust 14 C dates. The chronological framework of core ECS-DZ1 reveals striking sedimentation-rate changes. By comparison with other chronostratigraphical records, we infer that post-glacial deposition history (since ∼15 ka) of the study site is likely related to regional sea-level rise and delta-estuary environment evolution, as well as strengthened human activities and/or coastal currents. [ABSTRACT FROM AUTHOR]

Owing to the large and increasing population density in low-lying coastal regions, even small changes in sea level can have substantial societal and economic impacts. Alternations of terrestrial and marine sediments deposited in coastal areas or continental shelves are important and effective indicators of sea-level changes, and thus, have been widely studied in the marginal seas of China over the past 30 years. However, sea-level change results from not only eustatic factors but also tectonic activity. The Zhe-Min (or Zhejiang–Fujian) Uplift (ZMU) was such an important factor in geomorphology, and formed a barrier preventing entry of sea water into the northern marginal seas of China, but its Quaternary history is poorly known. In this study, a new borehole (ECS-DZ1) was drilled in the Zhoushan Islands, northern East China Sea to obtain information on the evolution of the ZMU during the Quaternary. Information from paleomagnetic and luminescence dating was combined with data on sedimentary changes. The main results are: (1) constrained by luminescence ages, the upper sedimentary units were extrapolated to have been deposited since ∼0.2 Ma; (2) paleomagnetic results suggest that the ECS-DZ1 borehole sequence spans from the pre-Olduvai Matuyama reverse chron to the Brunhes normal chron, approximately constraining the age of the basal sedimentary unit to ∼2.0 Ma; (3) a significant hiatus or erosion between two major sedimentary units possibly occurred between the late Early Pleistocene and Middle Pleistocene. As the Zhoushan Islands are within the ZMU and considering previous transgression studies around this region, it is inferred that the ZMU subsided at ∼2.0 Ma, allowing sea water to invade northward in the Yellow Sea basin. The ZMU might have been uplifted again no later than 1.0 Ma, causing a sedimentary hiatus or lacustrine development. After ∼0.2 Ma, the ZMU subsided completely, allowing large transgressions to develop across the northern marginal seas of China in the context of global sea-level changes. [ABSTRACT FROM AUTHOR]