Ouverture et evolution tectono-sedimentaire du golfe de Guayaquil: Bassin d'avant-arc neogene et quaternaire du Sud des Andes equatoriennes

The analysis of industrial seismic and well data of the Gulf of Guayaquil allows us to constrain the structure of the Gulf of Guayaquil. The main opening phase of the deepest South Ecuadorian Neogene and Quaternary fore-arc basin occurred during the Lower Pleistocene. It is located at the southern tip of the Dolores-Guayaquil megashear zone, between WNW-ESE normal faults and north-south transpressional structures. The processes from which it originated are similar to those of a pull-apart basin. It developed between the Dolores-Guayaquil megashear to the east, and the oblique convergent Nazca-South America plate boundary to the west. During the Upper Pleistocene, the sedimentation rate decreases drastically in relation to both the glaciation-related sea level falls and a transpressional event.