عنوان مقاله [English]
نویسندگان [English]چکیده [English]
The nature of most of hydrological behaviors of rivers depends on the dominant climatic and geologic conditions of environment during the past periods. The reasons of present behavior of fluvial networks will be understood by studying paleogeomorphological evidences. Although the overall flow direction of Ojan River (Aspas plain) is from south-east to north-west, the flow direction in west and east of the study area (Namdan and Bekan plains) and totally in trellis system of Kor, unlike the overall flow direction, is from north-west to south-east. In the study of river behavior, Nerontic system of drainage, figurative Geonerons, topography and geology relations (neural networks) were used instead of hydrology and precipitation relations. The results of this study reveal that, concurrent with climatic change of the study area during Quaternary and with ice melting in the middle of plain, Ojan basin was converted in to an isolated topogeoneron and created an independent fluvial basin within Kor basin and was adjoined to Kor rivers due to the cutting of basin by Boragh gorge. Then vast alluvial fans in south of basin were established and, like a barrier, prevented the flow toward Sivand river (Zaman Beig river). At first, Basin was converted in to a Paleotopogeoneron and lost its independence due to subsequent developments and became topogeoneron.