Hypsometric Properties of South Zagros Fold-Thrust Belt Basins: A Case Study in Namdan Basin in SW Iran

Abstract

Study area is located in Southwest Iran with relatively flat topography. Outcropped lithological units in the region belong from Triassic and Jurassic till recent era. The study area of the Namdan basin is related to the tectonic zone of the high Zagros region and the compressional-extensional regime. Geomorphic indices of active tectonics are useful tools to analyze the influence of activity. One of them is hypsometric integral which has generally been used to reveal the stages of geomorphic development. It is estimated by the graphical plot of the measured contour elevation and encompassed area by using empirical formulae. In constructing the hypsometric integral curve, a Digital Elevation Model (DEM) with 30 m spatial resolution has been used. This index is calculated in the study area. Then, based on index of its values, the hypsometric properties of drainage basins are analyzed in Namdan basin. Three different approaches were used for estimation of hypsometric integrals. The hypsometric integral values (HI) range between 0.18 and 0.31 for all the basins of study basin. In the study area, one stage of erosion cycle development, namely old stage is distinguished. Our results indicate that there is anomaly in Hi value which is located on faulted area. The results indicate the Northwest of Namdan basin and a small part of its Southeast are more active than other ones.