Typhoon-induced storms surges and river flooding events represent two types of natural disasters that affect a wide range, occurring with high frequency and causing serious societal losses. Due to the limited duration of instrumental records, there is an inadequate understanding of the patterns and mechanisms underlying the variations in typhoons and floods. The interpretation of sedimentary records aptly compensates for these deficiencies in terms of the temporal scale, becoming a crucial medium for extending the temporal span of typhoon and flood records. Previous studies in this field have primarily focused on the identification of single types of extreme events. The Changjiang Estuary, particularly Chongming Island, is significantly affected by both typhoons and river floods, making it an excellent area for synchronous comparative studies of these two types of extreme events. Based on the analysis of a core sample, ZP02, collected from Chongming Island, in terms of chronological, sedimentological, and geochemical characteristics, specific tracing fingerprints for event deposits from typhoon and flood events are established. Sediments from typhoon events generally exhibit erosive contact surfaces, coarser grain sizes, and a tendency to become finer upwards, often featuring layers mixed with coarse sand and shell fragments. In contrast, flood event deposits vary in grain size, either coarser or finer, with abrupt contact surfaces compared to normal sediment layers, and are predominantly brownish-yellow in color. The fingerprint tracing results indicate that the typhoon event layers are characterized by high values in principal component 2 (PC2) of the elements, Zr/Fe and Sr/Fe ratios, with low values in principal component 1 (PC1) the elements and Ti/Ca ratio. Flood event deposits are marked by high values in PC1 and Ti/Ca ratio, low values in PC2 and Sr/Fe ratio, and an increase in Zr/Fe ratio in coarser flood layers but no significant change in finer layers. Based on these fingerprints, 19 layers of typhoon and the same number of flood events were identified in core ZP02, which correspond well with documentary records. The establishment of tracing fingerprints for typhoon and flood event deposits provides methodological support for the identification and interpretation of various extreme event deposits.

中文翻译：

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新获得的沉积记录揭示了长江口崇明岛的台风和洪水发生情况

台风引发的风暴潮和江河洪水是影响范围广、发生频率高、社会损失严重的两类自然灾害。由于仪器记录的持续时间有限，人们对台风和洪水变化的模式和机制了解不足。沉积记录的解释恰如其分地弥补了这些时间尺度上的缺陷，成为延长台风和洪水记录时间跨度的重要媒介。该领域之前的研究主要集中在识别单一类型的极端事件。长江口特别是崇明岛受台风和河流洪水影响较大，是开展两类极端事件同步对比研究的绝佳区域。通过对崇明岛岩心样本ZP02的年代学、沉积学和地球化学特征进行分析，建立了台风和洪水事件沉积物的特异性示踪指纹。台风事件产生的沉积物通常表现出侵蚀接触面、较粗的颗粒尺寸，并且有向上变细的趋势，通常具有与粗砂和贝壳碎片混合的层。相比之下，洪水事件沉积物的颗粒大小各不相同，或较粗或较细，与正常沉积层相比具有陡峭的接触表面，并且颜色主要为棕黄色。指纹示踪结果表明，台风事件层的特征是主成分 2（PC2）元素、Zr/Fe 和 Sr/Fe 比值较高，而主成分 1（PC1）元素和 Ti/钙比率。洪水事件沉积物的特点是 PC1 和 Ti/Ca 比率值较高，PC2 和 Sr/Fe 比率值较低，较粗洪水层中 Zr/Fe 比率增加，但较细层中没有显着变化。根据这些指纹，在ZP02核心中识别出19层台风和相同数量的洪水事件，这与文献记录非常吻合。台风洪水事件沉积物溯源指纹的建立，为各类极端事件沉积物的识别和解释提供了方法支撑。