The well-¹⁴C–dated sediment core HM retrieved from the Yangtze River mouth was used to reconstruct the Holocene sedimentary–ecological complex of its incised valley. The complete Holocene sedimentary facies that were exclusively formed in the valley and evidenced by bio-geochemical measurement, showed the Latest Pleistocene fluvial facies to the Early-Holocene marine facies, and the Middle-Late Holocene deltaic facies. The established Holocene stratigraphic framework consists of 3 (I-III) infilling phases, of which phase I demonstrated the most rapidly infilling with coastal sediments into the valley (1.0 cm/yr), driven by the Early Holocene marine transgression. The remarkably low sedimentation rate of 0.1 cm/yr of phase II to the relatively low rate of 0.7 cm/yr of phase III occurred during the Middle-Late Holocene, reflecting sediments transported from river basin to directly fill in the valley along with deltaic depocenter shifted seawards as retrogressive processes. In addition, our microfossil (foraminifera and diatom) spectra displayed 3 distinctive biological stages with related sedimentary–ecological implications. During the Early Holocene, there were remarkably high numbers of diatom communities but few foraminifera, then followed a zone of less abundant microfossils between ca. 9.0–5.0 ka. After this time, richer foraminiferal communities appeared but diatoms were less abundant. The massive sediment infilling in the Early Holocene in the deeper (>60 m) incised valley would suppress benthic foraminiferal development, most likely due to anaerobic conditions in the lower water column. However, the flourishing diatom communities persisted in the brackish marine water associated with sea-level rise. The zone with fewer microfossils corresponded generally with the Middle Holocene sandy ridge formation at the core site, leading to poorer bio–preservation. After ca. 5.0 ka, foraminiferal communities gradually became adapted to the reduced salinity of the estuarine water associated with the deltaic progradation, though this appears not to have supported the diatom communities.

井^-14从长江口取回的C期沉积物核HM用于重建其切谷的全新世沉积生态复合体。完整的全新世沉积相完全在河谷中形成，并通过生物地球化学测量得到了证实，显示了到全新世早期的海洋相到最新的全新世河流相以及中新世晚期三角洲相。已建立的全新世地层框架包括3个（I-III）充填阶段，其中第一阶段显示了在早期全新世海侵的推动下，沿海沉积物向山谷（1.0 cm / yr）的充填速度最快。在中晚全新世期间，第二阶段的沉积速率非常低，为0.1厘米/年，而第三阶段的相对较低的沉积速率为0.7厘米/年，反映了从流域运来的沉积物直接进入山谷，同时三角洲沉积中心向海移动，这是一个退步过程。此外，我们的微化石（有孔虫和硅藻）光谱显示了3个不同的生物阶段，具有相关的沉积生态学意义。在全新世早期，硅藻群落数量非常多，但有孔虫数量却很少，然后在大约两个世纪之间跟随着一个数量较少的微化石区域。9.0–5.0 ka。在这段时间之后，出现了更丰富的有孔虫群落，但硅藻却不那么丰富。较新的早期（> 60 m）切开谷中的全新世早期大量沉积物将抑制底栖有孔虫的发育，这很可能是由于较低水柱中的厌氧条件所致。然而，蓬勃发展的硅藻群落持续存在于与海平面上升相关的咸淡海水中。微化石较少的区域通常与核心位置的中新世沙质脊形成相对应，导致生物保存较差。后约。5.0 ka，有孔虫群落逐渐适应了与三角洲发育相关的河口水盐度降低，尽管这似乎并没有为硅藻群落提供支持。