Rotated oceanic blocks in western Ecuador

Roperch, Pierrick; Mégard, François; Làj, C.; Mourier, Thomas; Clube, T. M. M.; Noblet, Christophe

doi:10.1029/gl014i005p00558

Cited by 44 publications

(36 citation statements)

References 13 publications

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“…The central part of the Talara Arc is bordered on the Andean side by the Huancabamba (or Cajamarca) Deflection (Fig. 1A) (for example Ganser, 1973;Roperch et al, 1987;Mourier et al, 1998). The changing direction of the Pacific side of the South American plate border is accompanied by significant variations in the width of the coastal margin and the Andean range.…”

Section: Geodynamical and Geological Settingsmentioning

confidence: 97%

Quaternary coastal uplift along the Talara Arc (Ecuador, Northern Peru) from new marine terrace data

Pedoja¹,

Ortlieb²,

Dumont³

et al. 2006

Marine Geology

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Section: Geodynamical and Geological Settingsmentioning

confidence: 97%

Quaternary coastal uplift along the Talara Arc (Ecuador, Northern Peru) from new marine terrace data

Pedoja¹,

Ortlieb²,

Dumont³

et al. 2006

Marine Geology

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“…1 and 3) was coeval with the development of the Macuchi island arc, on the not yet accreted Piñón-Naranjal oceanic terrane, and reflects a new subduction geometry. Since accretion was associated with clockwise rotation (Roperch et al 1987;Luzieux et al 2006), the new, Paleogene arc is oblique to the Late Creaceous island arc (Fig. 11).…”

Section: Late Cretaceous -Paleocene Evolution Of the Cop And Ecuadorimentioning

confidence: 99%

“…Finally, most of the accreted terranes of Ecuador underwent clockwise rotations since the Late Cretaceous, the amount of which varies from 20 to 120° (Roperch et al 1987;Luzieux et al 2006). Therefore, the Cretaceous orientation of the island arcs must be restored through a significant counterclockwise rotation.…”

Section: Preliminary Remarksmentioning

confidence: 99%

“…The creation of this southern subduction zone may be related to the collision of the northern edge of the COP against the Central American continental blocks (Donnelly et al 1990b;Iturralde-Vinente 1998;Pindell & Kennan 2001), and appears grossly coeval with the accretion of the San Juan terrane in Ecuador (Late Campanian, ≈ 75 Ma). It was associated with a significant colckwise rotation (Roperch et al 1987;Luzieux et al 2006). Scotese et al (1988) The accretion of the Guaranda terrane occurred in the Late Maastrichtian (≈ 68 Ma; Fig.…”

Section: Late Cretaceous -Paleocene Evolution Of the Cop And Ecuadorimentioning

confidence: 99%

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Accreted oceanic terranes in Ecuador: southern edge of the Caribbean Plate?

Jaillard

Lapierre²,

Ordóñez

et al. 2009

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The western part of Ecuador is made from several oceanic terranes, which comprise two oceanic plateaus, of Early (c. 120 Ma) and Late Cretaceous age (c. 90 Ma), respectively. The older oceanic plateau was accreted to the Andean margin in the Late Campanian (c. 75 Ma). Fragments of the Turonian–Coniacian plateau were accreted to the Ecuadorian margin in the Late Maastrichtian (c. 68 Ma, Guaranda terrane) and Late Paleocene (c. 58 Ma, Piñón–Naranjal terrane). The Guaranda terrane received either fine-grained oceanic sediments of Coniacian–Maastrichtian age, or island arc/back-arc volcanic suites of Middle Campanian–Middle Maastrichtian age. The Piñón–Naranjal terrane recorded a comparable history, completed in the Maastrichtian–Paleocene, either by pelagic cherts, or by island arc products (Macuchi arc). The Late Cretaceous plateau of Ecuador is interpreted as part of the Caribbean oceanic plateau (COP), because their evolutions are comparable. If so, the COP was not formed by the Galápagos hotspot, but on the Farallón oceanic plate, south of Ecuador and close to the South American margin. The COP belonged to the Farallón plate, until a subduction zone separated both plates in the Middle Campanian, giving way to a well-developed Mid Campanian–Mid Maastrichtian island arc. Accretion in the Late Maastrichtian triggered a change in the subduction system, and the development of a new arc system of Late Maastrichtian–Late Paleocene age, which crosscut the South America–COP plate boundary. The last accretion occurred in the Late Paleocene.

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“…[7] Coastal Ecuador has been characterized as allochthonous terranes of oceanic origin [Goosens and Rose, 1973;Lebrat et al, 1987;Roperch et al, 1987], accreted on the western side of the Andes, during several accretion episodes between Late Jurassic and Eocene (Figure 4). The last episode of Early Tertiary accretion involved oceanic plateaus and island arc terranes forming the coastal block and the Western Cordillera [Jaillard et al, 1997;Hughes and Pilatasig, 2002].…”

Section: Introductionmentioning

confidence: 99%

Shallow seismogenic zone detected from an offshore‐onshore temporary seismic network in the Esmeraldas area (northern Ecuador)

Pontoise

Monfret

2004

Geochem Geophys Geosyst

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[1] For a given site, many factors control the seismic risk. Earthquake magnitude, hypocentral distance, rupture mechanism, site effects and site vulnerability are among the most important. This article deals with one of these factors: the depth of the seismogenic zone, in the northern Ecuadorian subduction system, beneath a highly vulnerable site, the city of Esmeraldas and its industrial complex, the Ecuadorian oil refinery and shipping terminal. To address this problem, we analyzed data from a three weeks passive seismological experiment, conducted in the spring of 1998, using 13 Ocean Bottom Seismometers and 10 portable land-stations. A preliminary interpretation of wide-angle data obtained in the fall of 2000, in the Manta area, 100 km South of the study area, unambiguously indicates the presence of a velocity inversion in the Ecuadorian margin velocity structure. This velocity inversion is characterized by a shadow-zone of $1 s on the record-sections, and is interpreted as the result of a velocity contrast between the upper plate structure and the sedimentary and basaltic layer II of the subducted oceanic Nazca plate. One-dimensional velocity models are deduced from these wide-angle data and are used for earthquake location in the Esmeraldas area. This highly improved the hypocentral parameter determinations. The updip limit of the seismogenic zone is found at a depth of $12 km, 35 km eastward of the trench, and the depth of the seismogenic zone below the Esmeraldas city is found at $20 km. This shallow depth of the seismogenic zone dramatically increases the seismic hazard of the area.

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Rotated oceanic blocks in western Ecuador

Cited by 44 publications

References 13 publications

Quaternary coastal uplift along the Talara Arc (Ecuador, Northern Peru) from new marine terrace data

Quaternary coastal uplift along the Talara Arc (Ecuador, Northern Peru) from new marine terrace data

Accreted oceanic terranes in Ecuador: southern edge of the Caribbean Plate?

Shallow seismogenic zone detected from an offshore‐onshore temporary seismic network in the Esmeraldas area (northern Ecuador)

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