Longitudinal variations in cross-section morphology along a glacial valley: a case-study from the Tien Shan, China
Longitudinal variations in cross-section morphology along a glacial valley: a case-study from the Tien Shan, China
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DOI：
10.3189/172756501781832278
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发表时间：
2001
影响因子：
3.4
通讯作者：
L. Yingkui;Liu Geng-nian;Cui Zhijiu
中科院分区：
文献类型：
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作者：
L. Yingkui;Liu Geng-nian;Cui Zhijiu
摘要用变宽深比(VWDR)模型分析了冰川河谷断面形态的纵向变化。在VWDR中，山谷的横截面形状被表示为谷底以上不同高度处宽/深比的函数。两个参数m和n出现在模型中，m是谷底宽度的量度，n是谷面陡度的量度。我们利用VWDR模型研究了天山中段中国冰川河谷断面的形态变化，发现：(1)在没有支流的山谷中，从谷头到平衡线，m增加(谷底变宽)，n变得更负(谷侧变陡)，然后m减小，n变小，直到谷底；(2)在有支流的山谷中，观察到类似的模式，在支流进入主谷的河段，m有最大振荡，n最小。这些特征被认为反映了平衡线附近和汇合处冰川侵蚀潜力的最大化。
Abstract A new model, the variable width/depth ratio (VWDR) model, is used to analyze longitudinal variations in cross-section morphology along glacial valleys. In the VWDR, the cross-sectional shape of a valley is expressed as a function of the width/depth ratio at various heights above the valley floor. Two parameters, m, a measure of the breadth of the valley floor, and n, a measure of the steepness of the valley sides, appear in the model. We have used the VWDR model to study morphological variations of cross-sections along glacial valleys in the middle Tien Shan mountains, China, and find that: (1) in valleys without tributaries, m increases (the valley floor becomes wider) and n becomes more negative (valley sides become steeper) from the head of the valley to the equilibrium line, and then m decreases and n becomes less negative to the end of the valley; (2) in valleys with tributaries, a similar pattern is observed, with an oscillating maximum in m and minimum in n in those sections where a tributary enters the main valley. These characteristics are believed to reflect a maximization of glacial erosion potential in the vicinity of the equilibrium line and in locations of confluence.