Self-determining numerical modeling of compressional fault-bend folding

We present the application of the HCA (hybrid cellular automata) numerical modeling technique to the evolution of compressional fault-bend anticlines involving layers that have competency contrasts and a mechanical stratigraphy. The new modeling results show that, for competent hanging-wall layers, (1) the fault style is not preserved in the overlying fold; (2) fold development is not self-similar, and rotational growth wedges develop in the forelimb when syntectonic sedimentation occurs; and (3) balanced fault-bend anticlines can develop for ramp cutoff angles as high as 60°. These results compare favorably with field examples and laboratory analogues and dramatically broaden the applicability of fault- bend folding to model the evolution of thrust-related anticlines.