A model for the active origin and development of source-bordering dunefields on a semiarid fluvial plain: A case study from the Xiliaohe Plain, Northeast China
A model for the active origin and development of source-bordering dunefields on a semiarid fluvial plain: A case study from the Xiliaohe Plain, Northeast China
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半干旱河流平原源边沙丘活跃起源与发展模型——以西辽河平原为例
DOI：
10.1016/j.geomorph.2006.10.010
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发表时间：
2007-05
期刊：
影响因子：
3.9
通讯作者：
中科院分区：
文献类型：
--
作者：
在地球上的一些旱地已经发现了与水源接壤的沙丘田，但在大面积旱地的中国却鲜有报道。本文首次在国内报道了它们，并通过卫星图像分析和野外调查，提出了它们在半干旱河流平原上活跃的起源和发展模式。选取局域尺度和区域尺度的实例，分析了胶莱河、老哈河下游、乌里吉木伦河中下游（西辽河主要支流）所在的奈曼旗中部地区沙丘场的空间格局及其与河流系统的关系。从沙丘场的空间格局和河道动力学的角度来看，源区边缘沙丘的活跃形成和发展可分为四个阶段：第一阶段是河谷下风边缘的单个沙丘，流水不断侵蚀河谷的陡坡，下风坡朝向当地的优势风；第二阶段：个别局地尺度沙丘场的形成，是由陡峭的山谷坡的收缩和前缘沙丘的下风延伸，以及曲流的下游位移共同作用形成的；第三阶段：河道频繁侧向迁移，形成河谷下风边缘单个大型沙丘带；第四阶段：区域尺度沙丘，主要由气候变化或构造运动引起的河流改道形成。一方面，流水的横向迁移，特别是蜿蜒的横向迁移，为风成系统在风场和沙源上都准备了适宜的场所，并在充足的时间下，进一步使局部尺度的独立源缘沙丘带连接成区域尺度的沙丘带。另一方面，由于构造运动或显著的气候变化（在区域和千年尺度上），河流的改道必然会发生。因此，当一些沙丘带和邻近的河道被废弃时，新的河道在其他地方以同样的方式积极形成新的毗邻源的沙丘带，甚至在区域尺度上形成沙丘带。
Source-bordering dunefields have been reported in some drylands of the planet, but scarcely in China where there are extensive drylands. This article reports them in China for the first time, and presents a model for their active origin and development on a semiarid fluvial plain by means of satellite image analyses and field investigations. Local- and regional-scale examples are chosen to analyze the spatial patterns of dunefields, as well as the relationships with the fluvial systems in the central part of Naiman Banner where the Jiaolai River runs, and the lower Laoha River, and the middle and lower Ulijimulun River (principal tributaries of the Xiliaohe River). The active origin and development of source-bordering dunefields can be divided into four stages in terms of the spatial patterns of dunefields and channel dynamics: Stage I — individual dunes on the downwind margins of river valleys where running water constantly erodes the steep slopes of valley and where the downwind slopes orient to local dominant winds; Stage II — individual local-scale dunefields formed by deflation of the steep valley slopes and extending antecedent dunes downwind, together with the downstream displacement of meanders; Stage III — individual large-scale dunefield belts along the downwind margins of river valleys formed through frequent lateral migrations of channel; Stage IV — regional-scale dunefields formed mainly by river diversions due to climatic changes or tectonic movements. On the one hand, it is the running water's lateral migration, especially meandering, that prepares suitable places for aeolian systems in terms of both wind flow fields and sand sources, and subsequently it can further cause separate local-scale source-bordering dunefields to link together as a regional-scale dunefield belt given sufficient time. On the other hand, diversions of the river are bound to occur following changing hydrologic regimes resulting from tectonic movements or significant climate change (at regional and millennium scales). As a result, when some dunefield belts as well as the adjacent channels are abandoned, new channels work elsewhere in the same way to actively form new source-bordering dunefields and even dunefield belts at a regional scale.
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DOI：
10.3133/b2069
发表时间：
1994
期刊：
--
影响因子：
--
作者：
H. Markewich;William Markewich
通讯作者：
H. Markewich;William Markewich
影响因子：
3.5
作者：
Sweet
通讯作者：
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影响因子：
2.9
作者：
D. Muhs;C. Bush;Scott D. Cowherd;S. Mahan
通讯作者：
D. Muhs;C. Bush;Scott D. Cowherd;S. Mahan
影响因子：
3.9
作者：
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通讯作者：
J. Bullard;G. Wiggs;D. Nash
影响因子：
1.2
作者：
S. Pell;A. Chivas;I. Williams
通讯作者：
S. Pell;A. Chivas;I. Williams