The main rivers of the sahand Mt which drain water to two large basin ,flowing into deep valleys .Those valleys have analysed regarding the change of riverbeds and the type of channel profile and attention is focused on the concavity of the valley profiles on this basis ,we tried to determine the evolution of the Sahand,s valleys and thus estimate their long-term evolutionary tendencies.Regression analysis between relative distance and altitude was performed for the longitudinal profiles of 11 valleys in the Sahand mountain.Each profile can be expressed by one of exponential ,power ,logarithmic and linear functions.Most valley show a good fit to power functions.Dfferent function types show different curvature of the profiles.Valley fitted with exponentions have small curvature,those fitted with power functions have small curvature and those fitted with linear functions show almost straight lines.The valleys have grouped according to the mathematical models or function wich fits best: the exponential ,power ,logarithmic and linear functions.Finlly we tried to conclusion with traces in field.
Keywords: Geomorphlogical evolution,longitudinal valley profiles ,regression analysis , mathematical function ,Sahand Mt.
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