Fold Style Variations In Cover Sediments above Oblique Basement Faults, Qitoleh Anticline As a Case Study, North-West Zagros

The aspect ratio of folds is among the most important parameters indicating geometrical features of folds. Based on the aspect ratio, folds are categorized into two groups of buckle and forced folds. The NW-SE trending Qitoleh anticline, which is located in NW of the Lurestan structural subzone and in the vicinity of the High Zagros Fault, has unique structural characteristics that make it different other folds in the Zagros Folded Belt. In rock units older than Cretaceous, the anticline consists of four en-echelon buckle folds as shows high aspect ratio and forced fold geometry in Tertiary units. Such a variation in the fold style the surface down to the depth is interpreted as the imposed influence of the High Zagros Fault on intermediate detachment horizons. Such a fold style, which is also observed in other anticlines neighboring the SE part of High Zagros Fault, can be used as a model to interpret similar folds adjacent to the major reverse basement faults in other parts of the Zagros belt.