...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Earth Surface Processes and Landforms: The journal of the British Geomorphological Research Group >Sedimentary architecture of abandoned channel fills
【24h】

Sedimentary architecture of abandoned channel fills

机译：废弃河道填充物的沉积构造

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Channel fills are common elements of Holocene river systems and older fluvial sequences, but surprisingly little is known about formation and their sedimentary build-up. Abandoned channels result from channel shifting processes at various scales, including meander cutoff and channel-belt avulsion. Channel-fill sequences are of importance as containers of palaeoenvironmental proxy-records, can be used to reconstruct palaeochannel dynamics and derive palaeoflood records, and contain materials that allow dating the abandonment. Integrated knowledge on the dynamic nature (geometrical and physical insights) of channel abandonment and resultant sedimentary recording is a necessity for comparing and collating records from a series of abandoned channel fills. This paper intends to make channel-fill sedimentological sequences more useful recorders of channel abandonment processes and palaeofloods, for which improved understanding is needed of the internal build-up of channel fills. We review oxbow lake infilling along meandering rivers, and supplement this with highly detailed descriptions of two selected field examples of channel fills from the apex-region of the Netherlands' Rhine delta. From these examples it becomes clear that regional setting and type of abandonment result in different channel-fill end-members; oxbow cutoffs generally produce thick laminated clayey fills as the channel entrance is plugged rapidly, avulsion-abandoned channels are filled with coarse (proximal) deposits as a result of a maintained open river connection. Field examples of channel fills are integrated with knowledge on channel abandonment dynamics in meander cutoff and bifurcating river situations, including insights from recent numerical modelling. We propose a sedimentary-architecture descriptive scheme that distinguishes elements from two stages of channel-fill development; (i) the abandonment stage with initial proximal fill, and (ii) the subsequent fully abandoned palaeochannel that collects distal fill.
机译：河道填充物是全新世河系和较早河床序列的常见元素，但令人惊讶的是，人们对其形成及其沉积物了解甚少。废弃的河道是由各种规模的河道平移过程导致的，包括曲折截止和河道带撕脱。通道填充序列非常重要，因为它是古环境代理记录的容器，可用于重建古通道动力学并导出古洪水记录，并包含允许对遗弃进行年代估算的材料。关于通道遗弃的动态性质（几何和物理见解）以及由此产生的沉积记录的综合知识，对于比较和整理来自一系列废弃通道填充物的记录是必要的。本文旨在使河道填充物的沉积序列更有用的记录河道废弃过程和古洪水，对此需要进一步了解河道填充物的内部构造。我们回顾了蜿蜒河流沿岸的牛弓湖灌水，并通过对荷兰莱茵河三角洲顶点区域的两个选定的河床灌水实例进行了高度详细的描述，以此作为补充。从这些示例中可以清楚地看到，废弃的区域设置和类型导致了不同的渠道填充最终成员。当河道入口迅速堵塞时，牛弓截流物通常会产生较厚的层状黏土填充物，由于维持开放的河道连接，弃蚀废弃的河道充满了较粗的（近端）沉积物。渠道填充的现场示例与关于弯道截流和分叉河道中渠道放弃动态的知识相结合，包括最近的数值建模的见解。我们提出了一种沉积-建筑描述方案，该方案将要素与渠道填充发展的两个阶段区分开来。 （i）初期放弃近端充盈的放弃阶段，以及（ii）随后收集远端充盈的完全废弃的古通道。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号