OICC Press Iranian Journal of Earth Sciences 2228-785X 7 2 2015 03 21 Structural overview of the Halab-Gheydar area, southwest of Zanjan, NW Iran 50 58 EN Rasoul Esmaeili Department of Earth Sciences, College of Sciences, Shiraz University, Shiraz, Iran. Ali Faghih Department of Earth Sciences, College of Sciences, Shiraz University, Shiraz, Iran. Mahnaz Rezaian Department of Earth Sciences, Faculty of Sciences, Institute for Advanced Studies in Basic Sciences, Zanjan, Iran. Mohammad Ebrahimi Department of Geology, Faculty of Sciences, University of Zanjan, Zanjan, Iran. Journal Article 2015 03 21 Understanding the folding style of a fold-thrust belt is crucial to understand the nature and structural history of structures that may trap natural resources within the belt. In this research, the geometry and mechanism of a number of fault-related folds has been investigated based on field data and satellite image interpretations. The main study areas are: the Sohrevard and Ushtaniyan anticlines, Bahman and Halab synclines, and Gharahdagh, Halab, and Gheydar thrust faults, which have a NW-SE direction. These thrust faults control the morphology and structural framework of the Halab-Gheydar area. Geomorphic features of the folds suggest that they are fault-related folds. The structural style of the faults and associated folds indicate that these faults were reactivated during the Alborz deformation event.