More than 80% of marine organic carbon (OC) burial occurs in sediments of marginal seas. Sedimentary OC ¹⁴C ages up to several millennia older than co-deposited coastal and pelagic sediments have been well documented but the cause of this phenomenon remains uncertain. We measured ¹⁴C and ¹³C contents of OC, along with the sedimentary content of terrestrial and marine lipid biomarkers, in sediment cores from the East China Sea to evaluate and quantify processes controlling OC ages over the last 14.3 kyr. We find that ¹⁴C ages of OC were persistently older than co-deposited sediments by 1,930–5,530 yr. Temporal variations of the calculated apparent initial radiocarbon ages of total OC (TOC-AIR) mirrored sea level changes, with higher values (4,570±1,250 yr) during the transgression (14.1–7.8 kyr BP) and lower values (3,170±670 yr) during the mid-late Holocene (7.8–0 kyr BP), suggesting that transgression-induced coastline retreat reduced the transport of pre-aged terrestrial OC to the marginal sea. However, bulk OC ¹⁴C ages were consistently older than those expected from ternary mixing of Changjiang (Yangtze River), Huanghe (Yellow River) and marine sources based on δ¹³C and Δ¹⁴C end-members. We therefore propose that hydrodynamic processes during sediment transport and the addition of pre-aged OC from land and submerged coast were the main factors contributing to these old ¹⁴C ages of OC and their temporal variations. During the transgression, higher TOC-AIR values were observed during times of lower sea-level, which suggests that erosion of coastal deposits during transgression might have contributed old OC. Since sea level stabilized 7.8 kyr BP hydrodynamic processes were the primary cause of high ¹⁴C ages of OC. The significant role for hydrodynamic aging processes during the mid-late Holocene is hypothesized to result from longer transport distances between river mouths and sediment depocenters which can accommodate additional deposition-resuspension loops.

超过80％的海洋有机碳（OC）埋葬发生在边缘海的沉积物中。与共同沉积的沿海和中上层沉积物相比，沉积OC ¹⁴ C的年龄要高出几千年，但这种现象的原因仍然不确定。我们测量了东海沉积物芯中OC的¹⁴ C和¹³ C含量，以及陆地和海洋脂质生物标志物的沉积物含量，以评估和量化控制最近14.3年内OC年龄的过程。我们发现¹⁴OC的年龄比联合沉积的沉积物持续年龄要长1,930-5,530年。计算出的总OC（TOC-AIR）反映的海平面变化的表观初始放射性碳年龄的时间变化，在海侵（14.1–7.8 kyr BP）期间具有较高的值（4,570±1,250 yr），而较低的值（3,170±670 yr）在全新世中期（7.8-0 yr BP）期间，这表明海侵引起的海岸线撤退减少了老化的陆上OC向边缘海的运输。然而，本体OC ^14名Ç年龄始终高于从基于δ长江（长江），黄河（黄河）和海洋来源的三元混合预期的年龄较大的¹³ C和Δ ¹⁴C端成员。因此，我们提出，泥沙输送过程中的水动力过程以及陆上和淹没海岸中加入的过时OC是造成这些¹⁴ C老年龄及其时间变化的主要因素。在海侵期间，在海平面较低时观察到较高的TOC-AIR值，这表明海侵期间沿海沉积物的侵蚀可能是造成了老OC的原因。由于海平面稳定了7.8年BP的水动力过程是导致高¹⁴OC的年龄。据推测，在全新世中期晚期，流体动力老化过程的重要作用是由于河口和沉积物沉积中心之间的运输距离更长，可以适应额外的沉积-重悬浮循环。