Skip to Main content Skip to Navigation
Theses

Evolution of the forearc basins in Ecuador : from the accretion of oceanic allochthonous terranes to the uplift of the Andes and Coastal Cordilleras

Abstract : Ecuador offers a remarkable opportunity to study the evolution of forearc basins installed on accreted oceanic plateau. The interpretation of a network of industrial 2D-Multichannel Seismic Reflection profiles, calibrated with borehole data and regional stratigraphy, allowed to determine the main stages of the forearc evolution. The pre and syn-accretionary stages were documented in the current inner basins by Campanian volcanoclastic deposits sourced by the volcanic island arc which topped the oceanic plateau. NE dipping thrusts ruled shortening at the beginning of the oblique collision between the oceanic plateau and continental plate. Reverse faults and folds are synchronous with a regional erosion linked the end of the accretion during the early-middle Eocene. The forearc sensu-stricto domain is established coeval with the subduction of Farallón plate under South American plate. A regional extensional regimen initiated the double forearc basin configuration along the future Coastal Cordillera during the early Neogene. This phase coincides with the subduction of the Nazca plate, which marks the initiation of modern forearc basins. The basin subsidence during the Miocene was led by the orogenic building effects of the Andean reliefs. The segmentation of the margin is a response of regional uplifts related to strike-slip and reverse reactivation of inherited crustal faults during the Plio-Pleistocene ages. The collision and subduction of the Carnegie ridge explain the forearc segmentation and the coeval Costal Cordillera exhumation. This study provides a remarkable example of the evolution of a non-accretionary-type forearc basin influenced by volcanic ridge subduction.
Complete list of metadata

https://tel.archives-ouvertes.fr/tel-03376753
Contributor : Abes Star :  Contact
Submitted on : Wednesday, October 13, 2021 - 5:26:19 PM
Last modification on : Tuesday, November 16, 2021 - 5:19:10 AM

File

HERNANDEZ_SALAZAR_Maria_Jose_2...
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-03376753, version 2

Citation

María José Hernández Salazar. Evolution of the forearc basins in Ecuador : from the accretion of oceanic allochthonous terranes to the uplift of the Andes and Coastal Cordilleras. Earth Sciences. Sorbonne Université, 2020. English. ⟨NNT : 2020SORUS236⟩. ⟨tel-03376753v2⟩

Share

Metrics

Record views

84

Files downloads

44