عنوان مقاله [English]
A mountain glacier, when it occupies a river valley, immediately begins to change the cross-section and profile of that valley. River valleys in mountain areas tends to have V-shaped profiles. Glaciers work to widen as well as deepen their valleys and the typical cross-section of a glacial valley is U-shaped. The U-shaped glacial valley is one of the most characteristic of glacial landforms. With growth and spreading of ice cap in Sahand mountain in late quaternary (wurm), many of Sahand valleys (northern and northern west valleys) have about characteristic of glacial valley. But in comparison with Alpine landscapes, it has rather had development. In fact study of cross-profiles of Sahand glacial valleys and simulation model of form development, shows that these valleys are in third time step. The importance of cross-section of glacial valleys has made it the focus of this study. Therefore models of glacial valley development was used in Sahand glacial valleys. Graf relation, ratio of valley depth to its width, have coincidence only in a few case. Mathematical equation, Y=a Xb (where Y is the vertical, and X the horizontal distances from the midpoint of the valley bottom, a,b are constants) and other equations is used in one relatively typical glacial valley namely Ligvan Chay. Results show there is poor relation. Therefore glacial valley of Sahand mountains have had little evolution.
Keywords: Glacial erosion, Quaternary, Glacial valley, Cross profiles, Sahand mountains.