Alluvial fans are concerned to geomprhology because of their soil fertility, surface& groundwater availability and attractiveness for human settlements. Genetic processes and changing trend of fans are important from the geomorphic point of view.
Morphometric and geomorphic data , inferred by field surveys, aerial photos & satellite images, artographic measurements in the study area (Gamasiab basin in west of IRAN between Zagros mountains), used in statistical analysis and some geomorphologic inferences have made based on the analysis.
The study shows that: a) international researchers’ equations presented for relation between fans’ basins and cone extent , approved in the study area too, b) fans’ longitudinal profile & extent in the study area affected by tectonic activities and, c) lithology of fans catchment basin have obvious correlations to form &: extent of alluvial fans.
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