Situche Complex, Marañon Basin, Peru

Analysis of seismic profiles shows that the Situche Complex of the Marañon Andean foreland basin is composed of inverted extensional rollover structures related to westward dipping listric faults developed on flanks of salt domes or pillows. The presence of an intra-Jurassic unconformity cutting the salt structures shows that they are most likely Triassic-Jurassic in age. Sedimentary thickening observed in compensatory grabens or half-grabens, induced by the listric faults, shows that the extensional salt tectonics occurred mainly between the Santonian and the middle Eocene. The reverse offset of the Cenozoic reflectors shows that the extensional structures were partially or completely inverted during the Late Neogene.