Investigation of active tectonics related to Zardkooh fault and Nazi Bazaft salt dome using geomorphic indicators, southwestern Iran

Nazi salt dome is located in the border of high Zagros and folded Zagros in the northwest of Chaharmahal Bakhtiari province. This dome is affected by Zardkooh fault in the heights of Zard Kooh. The sequence of formations in the region includes Infra-Cambrian sedimentary rocks up to the present time The aim of this study was to investigate the active tectonics associated with Zardkooh fault and Nazi salt dome in Bazaft area in Chaharmahal and Bakhtiari province, using morphometric indices. Zardkooh fault is the border of high Zagros and folded Zagros. Zardkooh fault and Nazi salt dome are both exposed on the ground. In order to study the tectonics of the study area, the study area was first divided into 59 basins Then quantitative morphometric indices such as hypostometric integral index (Hi), drainage basin asymmetry index (Af), river gradient index (SL), basin shape index (BS), mountain front sinusitis index (Smf), relatively active tectonics index (Iat) has been calculated. In Hi index, 7 basins with active new tectonic activity, 21 basins with moderate tectonic activityand 31 basins with low tectonic activity were identified. Also in Af index, 18 basins with high and activetectonic activity, 21 basins with medium tectonic activity and 20 basins with low tectonic activity were determined. One high-activity basin, two basins with moderate tectonic activity and 56 basins with low tectonic activity were identified in the SL index. In BS index, 2 basins with active tectonic activity, 2 basins with moderate tectonic activity and 54 basins with low tectonic activity were identified. In Smf 16 index, the basin has active tectonic activity and the rest of the basins have low to very low tectonic activity. Relative activity index (IAT) in the study area indicates the presence of 3 basins with active tectonic activity, 26 basins with moderate tectonic activity and 30 basins with low tectonic activity are low. Based on the calculated indicators, the study area has different basin activities from medium to low. The data show that the activity of Zardkooh fault, the activity of the Nazi salt dome, large waterways in the region, and vegetation in the region have a significant impact on the activities of the region. The area has moderate to low new construction activity.