Investigating the geometry and mechanism of folding in Sulabder anticline (SW Iran)

Calculating the amount of shortening, the angle between ridges, the slope of the main thrust and the percentage of thinning of the front ridge compared to the back ridge in the middle and northwestern parts of Sulabder anticline shows the folding style related to fault propagation in these parts. The calculation of these geometrical parameters in the south-eastern part of the Sulabder anticline also shows the faulted detachment folding style. The change of folding class from 1c to 2 and 3, as well as the change of fold style from detachment folds to fault propagation style, are a sign of increased shortening, deformation progress and evolution of folding from the south-eastern part. This represents that in the initial stage the thrust fault system belongs to the middle and north-western parts, which are in the developed stages of the thrust fault system. The interpretation of seismic sections perpendicular to the Sulabder anticline in different sections shows that the Sulabder anticline in a raised wedge form is higher than the adjacent structures due to the action of the thrust faults on the northern and southern edges. In the Solabdar anticline, the performance and mobile behavior of marl-shale units of Pabdeh and Gurpi formations, due to its high thickness and formable rheology as an intermediate separation horizon, create different folding styles at the top and bottom of this unit. It also caused displacement in the axis of the upper and deeper parts of anticlines.