Optical dating of Holocene sediments from the Changjiang (Yangtze) delta, China

The Holocene sedimentary record from the Changjiang delta, eastern China provides an opportunity to document the evolution of coastal depositional systems and understand the variations of the East Asian summer monsoon. However, the chronology of the sediments is limited or questionable due to the limitation of the experimental technique and complicated sedimentary environment. In this study, two cores from Nantong and Taizhou in the Yangtze River Delta Region were taken to test the precision and accuracy in the optically stimulated luminescence (OSL) dating of sedimentary quartz. Seven samples from Taizhou and nine samples from Nantong were collected from the cores, and the SAR protocol was applied to the medium- and coarse-grained (45-63 μm and 90-125 μm) quartz. A preheat at 200 °C for 10 s and a cut heat at 160 °C for 0 s were used, followed by stimulation of the quartz OSL samples using blue light at 125 °C for 40 s. The results showed that the medium-grained quartz ages and coarse-grained quartz ages are generally consistent with each other within the limits of experimental errors and the stratigraphical order. In addition, we explored the potential of this approach by comparing OSL and ¹⁴C age estimates. Holocene sea-level changes will be discussed base on the new OSL ages.