DOI: 10.1016/j.tecto.2020.228374
论文题名: Evolution of the Ecuador offshore nonaccretionary-type forearc basin and margin segmentation
作者: Hernández M.J. ; Michaud F. ; Collot J.-Y. ; Proust J.-N. ; d'Acremont E.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2020
卷: 781 语种: 英语
中文关键词: Convergent margin
; Ecuador
; Multichannel seismic reflection
; Nonaccretionary forearc basin
英文关键词: Faulting
; Offshore oil well production
; Seismology
; Stratigraphy
; Convergent margin
; Early pleistocene
; Late Pleistocene
; Multichannel seismic reflection profiles
; Oblique subduction
; Strike-slip tectonics
; Structural evolution
; Transition zones
; Plates (structural components)
; accretionary prism
; continental margin
; depocenter
; faulting
; forearc basin
; plate convergence
; rifting
; segmentation
; seismic reflection
; strike-slip fault
; subduction
; Ecuador
; Manta
英文摘要: Forearc basins have developed along accretionary and nonaccretionary convergent margins. Here, we investigate the evolution of an offshore nonaccretionary-type forearc basin that has developed along the Ecuadorian convergent margin. We used 2D-Multichannel Seismic Reflection profiles to recognize five seismic units overlying the acoustic basement. The units were dated by correlation with wells and regional stratigraphy. They recorded the structural evolution of the margin into North, Central-North and Central-South margin segments identified from Gravity Free Air Anomalies. Intersegment transition zones accommodated deformation related to the margin segmentation, contributing to the development of shelf forearc depocenters. An offshore forearc basin (subunit L1a) developed on accreted oceanic terranes during the middle-to-late Eocene. The basin was affected by normal faulting during the Oligocene to early-middle Miocene (subunit L1b). This extension stage initiated during the rifting and oblique subduction of the Farallon plate beneath the Ecuador margin. The basin underwent an early-middle Miocene uplift outlined by unconformity U1 potentially associated with the subduction of the young Nazca plate, in a less oblique plate convergence environment. During the early-Pliocene, the Central-South margin segment individualized by uplift during the formation of unconformity U2. The Manta anticline, which developed in the intersegment transition zone, accommodated the segmentation. This event is associated with the arrival of the Carnegie ridge in the subduction. The North segment individualized by uplift during the Pliocene early-Pleistocene formation of the Pedernales structural high, which may coincide with a reactivation of the Canandé fault. Synchronously, unit L3 sediment recorded the subsidence of the Central-North segment, and strike-slip tectonics in the area of the Jama-Bahía depocenter. A mosaic of middle-to-late Pleistocene unit L5 depocenters that alternate with uplifted zones along the shelf likely recorded the subduction of the topographically irregular Carnegie ridge. The study provides a remarkable example of the evolution of a non-accretionary-type forearc basin. © 2020 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170602
Appears in Collections: 气候变化与战略
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作者单位: Departamento de Geología, Escuela Politécnica Nacional, Ladrón de Guevara E11 – 253, Quito, Ecuador; Université Côte d'Azur, IRD (Institut de Recherche pour le Développement), (CNRS), Centre National de la Recherche Scientifique, Observatoire de la Côte d'Azur, GEOAZUR (laboratoire Géoazur), Valbonne, 06560, France; Sorbonne Université, Institut des Sciences de la Terre de Paris (ISTeP), Campus Pierre et Marie Curie, Paris, 75252, France; Sorbonne Université, Faculté des Sciences et Ingénierie, Paris, F-75252, France; Géosciences Rennes, CNRS, Université de Rennes 1, Campus de Beaulieu, Rennes cedex, 35042, France
Recommended Citation:
Hernández M.J.,Michaud F.,Collot J.-Y.,et al. Evolution of the Ecuador offshore nonaccretionary-type forearc basin and margin segmentation[J]. Tectonophysics,2020-01-01,781