地质学
沉积物
沉积作用
沉积岩
分类
地貌学
冲积层
全新世
漫滩
泥沙输移
水文学(农业)
河流
地球化学
古生物学
岩土工程
构造盆地
生态学
计算机科学
生物
程序设计语言
作者
Alessandro Sgarabotto,Elena Bellizia,Alvise Finotello,Andrea D’Alpaos,Stefano Lanzoni,Jacopo Boaga,Giorgio Cassiani,Massimiliano Ghinassi
出处
期刊:Geological Society, London, Special Publications
[Geological Society of London]
日期:2023-07-25
卷期号:540 (1)
标识
DOI:10.1144/sp540-2022-220
摘要
Abstract Many present-day alluvial floodplains display traces of abandoned meandering channel belts developed during the past millennia (i.e. mid to late Holocene). Deposits of these ancient rivers represent preferential pathways for groundwater flows and related environmental issues, such as contaminant propagation or saltwater intrusion in coastal areas. However, since formative bankfull flows in such old and abandoned routes are hard to estimate, fossil meanders have not been commonly addressed by morphodynamic numerical models, and most of them have been investigated following classical sedimentological approaches based mainly on punctual data derived from sedimentary cores. This study aims at investigating the sediment distribution within different fossil bends on the southern Venetian Plain (NE Italy), and relating such distribution to numerically modelled bed shear stresses used herein as a proxy of sediment sorting patterns. For this purpose, formative flows in the studied palaeomeanders are first inferred from measured sediment grain size and estimates of bend widths. Then, shear stress distributions are computed along the studied palaeobends using a 2D linearized model. Model results are finally compared with conductivity distributions gauged directly in the field through electromagnetic induction investigations in the frequency domain. Our results suggest significant correlations between shear stress distributions and sediment sorting estimated from conductivity data. We deem that the integration between sedimentological reconstructions and state-of-the-art numerical modelling can provide a solid contribution to predicting the spatial distribution of sediment properties within ancient meandering channel belts, with relevant implications for the understanding of shallow aquifer dynamics and soil management.
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