Refolding structures in the Aliaga area (Iberian Chain, Spain) show how erosion can exert a control on the geometry of buckle fold interference. Early Miocene ENE-trending buckle folds are superposed on a large NNW-SSE anticline (Eocene–Oligocene). North of Aliaga, the earlier hinge zone in the competent limestone unit controlling buckling (Urgon facies, Lower Cretaceous) constitutes a mechanical obstacle to refolding, which induces development of essentially conical type 2 interference. To the south, erosional removal of the hinge zone at that competent unit allowed the near-vertical eastern limb to behave as independent layers, being refolded into cylindrical, near-vertical-axis folds showing a snake-like map pattern. Lower Miocene conglomerates containing pebbles of Jurassic origin, whose source area was the core of the earlier NNW-SSE–trending anticline, indicate that this Jurassic core had been effectively exhumed before refolding occurred. In this way, snake-like folds constitute a new case of erosion-controlled tectonic structure.

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