Linking backbarrier lacustrine stratigraphy with spatial dynamics of shoreline retreat in a rapidly subsiding region of the Mississippi River Delta
Linking backbarrier lacustrine stratigraphy with spatial dynamics of shoreline retreat in a rapidly subsiding region of the Mississippi River Delta
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DOI：
10.1016/j.geomorph.2021.108008
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发表时间：
2021-11-10
期刊：
影响因子：
3.9
通讯作者：
Yao, Qiang
中科院分区：
文献类型：
--
作者：
Dietz, Marianne E.;Liu, Kam-biu;Yao, Qiang
墨西哥湾北方海岸线正在迅速后退，废弃的密西西比河三角洲复合体的海岸特征正在侵蚀和下沉。海湾香槟位于Caminada-Moreau岬，该地区位于目前活跃的三角洲以西，是全球撤退和土地损失率最高的地区之一。因此，在过去的130年里，香槟湾的海岸线已经后退了两公里多，导致从一个稳定的圆形淡水湖逐渐过渡到一个经常受到干扰的半圆形后障泻湖。对过去十年在该地点收集的一系列沉积物岩心中的碎屑层进行的分析表明，该湖过去受到的扰动较少，随着海岸线的后退，对热带气旋造成的海洋入侵事件变得越来越敏感。岩芯的地球化学和花粉分析也揭示了香槟湾在过去世纪的环境和化学条件的深刻变化。通过与地层的空间变化从卫星图像上观察到的，这项研究建立了一个时间轴的过渡湾香槟从内陆湖的backbarrier环境，并证明，这些变化并没有发生在一个恒定的速率。这些结果提供了一个案例研究，改变当地的环境条件，以应对快速海岸线撤退，因此作为未来的沿海变化的路易斯安那州和其他海湾沿岸地区的模型。(c)2021年由Elsevier B. V.出版
The northern Gulf of Mexico shoreline is rapidly retreating, and coastal features of the abandoned Mississippi River delta complexes are eroding and subsiding. Bay Champagne is located in the Caminada-Moreau headland, a region located west of the currently active delta that has one of the highest rates of retreat and land loss globally. As a result, the shoreline at Bay Champagne has retreated more than two kilometers in the past 130 years, causing a gradual transition from a stable, circular freshwater lake to a frequently disturbed, semi-circular backbarrier lagoon. Analyses of clastic layers in a series of sediment cores collected at this site over the past decade indicate the lake was less perturbed in the past and has become increasingly more sensitive to marine incursion events caused by tropical cyclones as the shoreline retreated. Geochemical and pollen analyses of the cores also reveal profound changes in environmental and chemical conditions at Bay Champagne over the past century. Through relating stratigraphy to spatial changes observed from satellite imagery, this study establishes a timeline of the transition of Bay Champagne from an inland lake to a backbarrier environment, and demonstrated that these changes have not occurred at a constant rate. These results provide a case-study of changing local environmental conditions in response to rapid shoreline retreat, and therefore serve as a model for future coastal changes for Louisiana and other Gulf coastal areas. (c) 2021 Published by Elsevier B.V.