Sediment source identification is critical for understanding delta evolution processes and for managing delta sustainability, particularly for deltas experiencing significant recent fluvial sediment discharge. Sediment sources for the Yangtze River Delta (YRD) are commonly assumed to be derived from the Yangtze River, despite the fact that the YRD is a tide-dominated delta that can receive marine-sourced sediments in addition to fluvial inputs. In particular, potential contributions from the neighbouring sediment-laden Yellow River, when it discharged into the Yellow Sea during 1128–1855 CE, remains unclear. Here we present provenance analysis of three cores from the northern YRD using size-specific magnetic characterizations. We find that magnetic properties of sediments younger than ~400 years have large differences among the studied cores. Comparison of magnetic properties to potential sources, including the major Yangtze River tributaries (i.e., Jinsha River, Jialing River, and Han River) and Old Yellow River (OYR), indicates that the northern core received enhanced Yellow River sediment loads over the last 400 years, while the southern core had a dominant Yangtze influence, which is most pronounced in size fractions less than 16 μm. This interpretation is supported by geochemical results. The documented spatial sediment source heterogeneity is caused by differences in tidal-fluvial interaction among delta distributary channels. Our results imply that the neighbouring OYR delta to the north exerts a remote influence on the YRD through longshore transport. This coastal connectivity between deltas should be assessed when forecasting future tide-dominated delta changes in the context of global change.

沉积物源识别对于理解三角洲的演化过程和管理三角洲的可持续性至关重要，特别是对于近期河流沉积物大量排放的三角洲而言。尽管长江三角洲是一个以潮汐为主的三角洲，除了河流输入外，还可以接收海洋沉积物，但通常认为长江三角洲的沉积物来源是长江。尤其是，尚不清楚相邻的载有黄河的黄河在公元1128年至1855年之间排入黄海时的潜在贡献。在这里，我们使用尺寸特定的磁特性描述了来自北部长三角地区的三个岩心的物源分析。我们发现小于400年的沉积物的磁学性质在所研究的岩心之间有很大的差异。将磁特性与潜在来源（包括主要的长江支流（金沙江，嘉陵江和汉江）和老黄河（OYR））的磁特性进行比较表明，在最近的400年中，北部核心地区的黄河沉积物负荷增加了年，而南部核心地区在长江中起着主导作用，其大小分数小于16μm最为明显。这种解释得到了地球化学结果的支持。已记录的空间沉积物源异质性是由三角洲分布河道之间的潮汐-河流相互作用的差异引起的。我们的结果表明，北部的邻近OYR三角洲通过长岸运输对YRD产生了遥远的影响。