In order to study the carbon burial rates and sources of early to middle Holocene sediments in the Changjiang River palaeo-valley area, the determination of total organic carbon (TOC), total nitrogen (TN) and δ¹³C of sediments from ZK1 hole was carried out, and the spatial and temporal distribution characteristics and TOC sources of carbon burial in the Changjiang River palaeo-valley were analyzed by combining AMS¹⁴C (plant debris, shells) dating, foraminiferal and grain size data. Using a combination of historical geography and sedimentary geology combined with AMS¹⁴C data, the chronostratigraphic classification was carried out from bottom to top as tidal channel (U1), estuarine bay (U2), tidal sand ridge (U3), and pre-delta (U4). Sediments were influenced by the effects or factors of water depth, runoff, estuarine after-circulation, tidal currents, waves, storms and remineralization, and the mean value of TOC was 0.41%, which was lower than the surface layer of the Changjiang River Estuary. The ZK1 hole carbon burial flux (TOC_BF) ranged from 7.4 g/(m²·a) to 110.5 g/(m²·a), with large variations. The TOC_BF values were mainly controlled by the sedimentation rate. The results of δ¹³C and TOC/TN (C/N) projection points indicate that there are TOC sources with multi-source characteristics, and the overall performance is partial to terrestrial sources. The linear fit correlation between C/N and δ¹³C was high, which allowed the quantitative analysis of organic matter sources using C/N and δ¹³C. The organic carbon source analysis was carried out based on C/N and δ¹³C using a three-terminal source model. The U2 and U3 depositional periods were in the Holocene Great Warm Period, and the sea-derived and land-derived carbon was higher than that of the U1 and U2 depositional units, which was mainly related to the increase of marine and terrestrial primary productivity. The mean contribution of marine phytoplankton to total organic carbon was 31% in ZK1 hole. The mean contribution of estuarine phytoplankton to total organic carbon was 31%; the mean contribution of terrestrial organic carbon to total organic carbon was 38%. Overall, the contribution of terrestrial organic carbon was greater than that of estuarine phytoplankton and marine phytoplankton, which was basically consistent with the analysis results of the graphical method.

organic carbon  /  foraminifera  /  burial rate  /  depositional environment  /  AMS¹⁴C