Conical drag folds as kinematic indicators for strike-slip fault motion

Conical drag folds are developed in the vicinity of faults where rock sequences with significantly different mechanical properties are subjected to oblique shear. The drag folds formed by passive rotation of a competent bed surrounded by flowing incompetent media. Mesoscale conical drag folds can serve as kinematic indicators. The conical fold axis coincides with the rotation axis of slip, and the angle θ between the small circle of poles to bedding and the conical axis is equal to the angle between the pole to tilted bedding and the rotation axis of slip. The sense of asymmetry of the drag fold reflects the sense of shear. The relationship between conical folding and sense of shear established for the mesoscale can be applied to larger fault zones. For example, the geometry of conical drag folds along with other fault-related structures reveal sinistral strike-slip motion in the Mount Arif area of the Negev.