Revision estratigrafica del cretaceo superior del Noroeste peruano y Suroeste ecuatoriano : datos preliminares, consecuencias tectonicas

The stratigraphic revision of the Cretaceous series of Northwestern Peru and Southwestern Ecuador shows that, subsequently to the Albian transgression, three distinct forearc sedimentary basins were formed. These are the turbidity-filled Lancones-Celica Basin (Late Albian to Coniacian or Santonian), the Paita-Yunguilla Basin mainly filled by shales (Middle Campanian to Middle(?) Maastrichtian), and the Talara Basin s.s. (latest Paleocene-earliest Eocene to Late Eocene). This succession evidences the occurrence of three major tectonic-sedimentary events of Late Albian (Mochica phase), Late Santonian-Early Campanian (Peruvian phase) and Late Maastrichtian and/or Paleocene age, respectively. Geological mapping shows that the Lancones-Celica Basin includes at least three different paleogeographic units, the juxtaposition of which occurred prior to the deposition of the Campanian-Maastrichtian shales. The Santonian-Campanian tectonic event was associated with a noticeable deformation. During the Tertiary, the deformation and the Eocene sedimentation seem to have been controlled by major NE-SW-trending faults, which partly control the present-day topography. (Résumé d'auteur