Tropical mangrove swamps are commonly characterized by dense networks of tidal channels that may show pronounced meandering and dendritic patterns. Channel meanders are sometimes accompanied by cut-offs, and, like classical fluvial meanders, record changes in hydrology and sedimentation over time. Channel meandering can, thus, be an important process that contributes to spatial and temporal variability in the preserved record of the sedimentology and geochemistry of mangrove sediments. The aim of this study is to highlight changes in channel meander sedimentation in response to a meander cut-off in a tropical mangrove swamp. Two short sediment cores were sampled, respectively from a point bar (core KR1, 122 cm) at the junction with the neck cut-off and inside the cut-off (core KR2, 98 cm) in the Sungai Kerteh mangroves of Peninsular Malaysia. The profile comparison was based on sediment characteristics, total organic carbon (TOC), and selected elements (Fe, Na, Mg, Mn, Ba, and Sr). A smaller standard deviation of mean grain size (MGS) was found at the point bar (4.37 ± 0.51 ϕ) than in the cut-off (4.43 ± 1.76 ϕ), indicating a difference in flow velocity between the two settings. In turn, these changes in grain size influence channel meander evolution via associated changes in TOC and heavy metals. In order to clarify these relationships, we used principal components analysis and factor analysis. An increased accumulation of selected elements and TOC at the cut-off site from a depth of ~ 60 cm to the core-top segment was probably associated with a slowing down of sediment settling. A higher TOC recorded in the cut-off (2.74 ± 1.42%) compared to the point bar (1.14 ± 0.46%) suggests a propensity for prolonged in situ accumulation of organic matter in the abandoned meander bend. This study provides grain size and sediment geochemical information that is consistent with patterns of active and inactive sedimentation in the meander bends of mangrove channels.

中文翻译：

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马来西亚半岛Sungai Kerteh热带红树林河道中的沉积和沉积物地球化学

热带红树林沼泽通常以潮汐通道密集的网络为特征，这些网络可能显示出明显的蜿蜒和树突状分布。河道弯道有时会伴有断流，并且像传统的河流弯道一样，记录水文和沉积物随时间的变化。因此，河道蜿蜒可能是一个重要的过程，有助于保存红树林沉积物的沉积学和地球化学记录的时空变化。这项研究的目的是强调热带红树林沼泽中河道截断响应河道截断的变化。在马来西亚半岛的Sungai Kerteh红树林中，分别从与颈部边界的交界处的一个点棒（核心KR1，122厘米）和内部边界（核心KR2，98厘米）中的两个短沉积物岩心中取样。剖面比较基于沉积物特征，总有机碳（TOC）和选定的元素（铁，钠，镁，锰，钡和锶）。与截止点（4.43±1.76 ϕ）相比，在点棒（4.37±0.51 ϕ）处发现了平均晶粒尺寸（MGS）较小的标准偏差，表明这两种设置之间的流速差异。反过来，这些晶粒尺寸的变化会通过TOC和重金属的相关变化影响通道曲折的演变。为了阐明这些关系，我们使用了主成分分析和因子分析。从〜60 cm深度到岩心顶部段，截止点处选定元素和TOC的积累增加可能与沉积物沉降速度减慢有关。与点栏（1.14±0）相比，截止值记录的TOC更高（2.74±1.42％）。46％）表明在废弃的弯曲弯道中有机物长期原位积累的趋势。这项研究提供的粒度和沉积物地球化学信息与红树林河曲折弯中活跃和非活跃沉积的模式一致。