Combined chronological and mineral magnetic approaches to reveal age variations and stratigraphic heterogeneity in the Yangtze River subaqueous delta

Luminescence characteristics of muddy sediments in the turbidity maximum zone of the Yangtze River mouth and implications for the depositional mechanisms

“…The less depleted δ 13 C values observed in both cores KZ01-A and KZ02 are indicative of a major contribution from marine-sourced organic carbon in the delta front setting (Figure 5; Niu et al, 2021). The offshore inputs into the Yangtze River mouth have been reported in many previous studies (e.g., Du et al, 2010;Ge et al, 2020;Wang et al, 2021) and surficial sediments in the subaqueous delta have yielded OSL ages exceeding 1,000 a (e.g., core A5-4 in Cheng et al, 2020; see Figure 1B for the core location). When older sediments are imported into the river mouth by processes such as tidal pumping, estuarine circulation induced by saltwater intrusion, and storm events (Warner et al, 2008;Cho et al, 2012;Li et al, 2016;Burchard et al, 2018;Wang et al, 2020), they are less likely to be bleached because the stratified water column suppresses turbulence and the sediments have no chance to be dispersed to the water surface.…”

“…The bathymetry map of 1842 CE is based on the marine chart of the British Navy. Core A5-4 was collected from Cheng et al (2020). Core HM was collected from Nian et al (2021).…”

Greigite as an Indicator for Salinity and Sedimentation Rate Change: Evidence From the Yangtze River Delta, China

“…In contrast, magnetic, measurements are simple and quick, allowing for high resolution stratigraphic division and paleoenvironmental studies. Considering the heterogeneous nature of delta deposits in space and time, as demonstrated by the three cores in this study and previous studies in the area (Cheng et al., 2020), our approach has wider implications in paleoenvironmental studies using delta deposits.…”

“…The multiple greigite peaks in the composite layer (C1) probably reflect fluctuating depositional conditions over a short period that is, 10–9 ka according to the dating results (Figure 2). The more frequent fluctuations in the thicker C1 layer of core CM02, in comparison to the other two cores, also reflects the spatial variability of depositional processes (Cheng et al., 2020). Integrated with high‐resolution dating, magnetic measurements could therefore offer paleoclimatic and environmental variability information on a centennial scale.…”

“…Therefore, we see a lower level of iron sulfide accumulation including greigite. The greigite layer is not present in core CM02, which highlights the spatial heterogeneity of sedimentary conditions in delta environments (Cheng et al, 2020).…”