Luminescence dating of core DLC70-2 from the North Yellow Sea in China and its implication for late Quaternary transgressions

Reliable chronology is crucial for reconstructing the sedimentary history and sea level fluctuations. However, the lack of robust ages for late Quaternary deposits on the North Yellow Sea (NYS) shelf hampered our understanding of its sedimentary processes. In this study, quartz optically stimulated luminescence (OSL) and feldspar post-infrared (IR) IR stimulated luminescence (pIRIR) dating protocols were utilized to establish a detailed chronostratigraphy for the upmost 30 m of core DLC70–2 from the central NYS. Based on lithology features and foraminifera assemblages, we identified three transgressive layers (T1, T2 and T3), corresponding to U1 (0–5.0 m), U3 (10.0–18.5 m) and U5 (23.3–30.0 m), respectively. In U1, two OSL and six radiocarbon ages of 4.9–10.3 ka indicate T1 deposition during Marine Isotope Stage (MIS) 1. For U2, three quartz OSL and one feldspar pIRIR ages ranging from >67 ± 7 to 45.1 ka suggest U2 deposition during MIS 4 - early MIS 3. However, due to quartz OSL signal saturation (D_e over 150 Gy), five OSL ages from U3 sediments only yield minimum ages of >73 ± 8 to >53 ± 4 ka. While the feldspar age of 76 ± 7 ka at 10.25 m in upper U3 indicates that T2 was formed no later than MIS 5. Significant underestimation in previous published ¹⁴C dates for pre-Holocene sediments was detected by cross-checking between OSL and ¹⁴C ages. In U5, a fading corrected feldspar age of 191 ± 17 ka at depth of 23.65 m suggests that T3 has formed at least during MIS 7. We reconstruct a comprehensive late Quaternary stratigraphy using ten cores obtained from the Bohai Sea (BS) and Yellow Sea (YS) and the current renewed chronostratigraphy of core DLC70–2. The occurrence of cold-water species Buccella frigida and Protelphidium tuberculatum during MIS 5 indicates there existed a cold-water mass (cyclonic eddy) similar to present-day marine circulation. Additionally, the late Quaternary stratigraphic correlation is supported by the previously chronostratigraphic reconstruction of coastal loess. These findings will enhance our comprehending on the sedimentary processes and their paleo-environment changes on the eastern Chinese shelves during late Quaternary.