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Article Dans Une Revue Journal of South American Earth Sciences Année : 2023

Structural evolution of the southern Ecuadorian forearc in the Santa Elena Peninsula region

Cédric Bulois
Marianne Saillard
Nicolas Espurt
Andréa Peuzin
Laure Schenini
Marc Régnier
  • Fonction : Auteur
Gueorgui Ratzov
  • Fonction : Auteur

Résumé

The southern Ecuadorian forearc system is related to the subduction of the oceanic Farallon/Nazca Plate beneath the continental South American Plate since the Late Cretaceous, and currently evolves with the dynamic of a tectonic block called North Andean Sliver. To explore the structural architecture and processes controlling the Upper Cretaceous-Cenozoic growth of the forearc, we built a ~143 km-long onshore-offshore crustal-scale crosssection in the Santa Elena Peninsula region using seismic reflection profiles and well and field data. The structure of the Santa Elena Peninsula forearc system is controlled by imbrication of Upper Cretaceous-Palaeocene oceanic basement and Cenozoic sedimentary units, and underplating of distal Cenozoic sequences stacked at the trench zone. This led to the progressive construction of an accretionary wedge through time. The forearc substratum is mainly formed by the Upper Cretaceous-Palaeocene basement developed during the docking of oceanic terranes. It is later deformed by NW-trending landward-dipping, normal to strike-slip faults during the Middle Eocene, and renewed compression by inversion of inherited faults from the Oligocene onwards. Recent deformation consists in N-trending oceanward-dipping normal faults in the frontal slope domain and fault-controlled uplift of marine terraces along the coastal area. Therefore, the Upper Cretaceous to present-day structural evolution of the Santa Elena Peninsula forearc is controlled by the long-lasting subduction dynamics and structural inheritance of the upper plate.
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Dates et versions

hal-04233625 , version 1 (09-10-2023)

Identifiants

Citer

Cédric Bulois, Marianne Saillard, Nicolas Espurt, Pedro Reyes Benítez, François Michaud, et al.. Structural evolution of the southern Ecuadorian forearc in the Santa Elena Peninsula region. Journal of South American Earth Sciences, 2023, 130, pp.104503. ⟨10.1016/j.jsames.2023.104503⟩. ⟨hal-04233625⟩
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