Holocene evolution of meander bends in lowland river valley formed in complex geological conditions (the obra river, poland)
Holocene evolution of meander bends in lowland river valley formed in complex geological conditions (the obra river, poland)
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复杂地质条件下形成的低地河谷曲流弯曲的全新世演化（波兰奥布拉河）
DOI：
10.1111/geoa.12029
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
M. Słowik
中科院分区：
文献类型：
--
作者：
M. Słowik
摘要通过探地雷达测量、取芯以及卫星和航空图像分析，研究了在不同地质条件下形成的曲流弯演变的差异。这项研究是在巴西艾弗（西部的奥地利）的下游进行的，其地质特征非常复杂：山谷的特定部分是在冰川、死水和冰川沉积物中形成的。这项研究是在四个详细的研究地点进行的，代表了曲流弯曲的不同形成条件。曲流可分为四种类型：横向迁移曲流，其特征是迁移方向频繁变化，并伴有河床撕脱和截断;曲流，其连续迁移的痕迹受到死水盆地沉积物的限制;局限于冰川冰碛形成的狭窄山谷中的曲流，其特征是出现了河道中的岛屿;曲流河是人类活动影响下的河床迁移和强烈的漫滩淤积的复杂变化的痕迹。此外，还发现了胸罩谷早期发展的痕迹和多通道模式的遗迹。研究结果还表明，尽管形成于不同的地质条件下，在过去的7000年中，在每个站点的洪泛区结构中记录了类似数量的曲流迁移阶段。它还发现，所研究的河曲的发展是缓慢的情况下，积极迁移的曲流河。
Abstract Ground‐penetrating radar surveys, coring and the analyses of satellite and aerial images have been carried out to study differences in the evolution of meander bends formed in various geological conditions. The research was conducted in the lower course of the bra iver (western oland) characterized by a complex geology: particular sections of the valley were formed in glacial, stagnant water and fluvioglacial deposits. The research was conducted in four detailed study sites representing different formation conditions for the meander bends. Four types of meanders were distinguished: laterally migrating bends characterized by frequent changes of migration direction accompanied by river bed avulsions and cutoffs; bends with traces of continuous migration limited by stagnant water basin deposits; confined meanders in a narrow valley formed in glacial till characterized by the occurrence of mid‐channel islands; and meanders with traces of complex changes of the river bed migration influenced by anthropogenic intervention followed by intensive overbank deposition. Moreover, traces of an early development of the bra valley and remains of multi‐channel pattern were discovered. The results also show that despite being formed in different geological conditions, a similar number of the meander migration phases were recorded in the floodplain architecture during the last 7000 years at each of the sites. It is also found that the development of the studied meanders was slow compared with cases of actively migrating meandering rivers.