Geological history of the Cretaceous ophiolitic complexes of northwestern South America (Colombian Andes)

Bourgois, Jacques; Toussaint, Jean‐François; González, Humberto E.; Azéma, Jacques; Calle, Bernardo; Desmet, Alain; MURCIA, LUIS ANDRES GUERRERO; Acevedo, Alvaro P; Parra, Eduardo; Tournon, Jean

doi:10.1016/0040-1951(87)90215-0

Cited by 56 publications

(22 citation statements)

References 15 publications

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“…This is a unique case for the Mesozoic in the Andes or along the eastern Pacific subduction zones, although some authors have proposed similar back-arc basins floored by oceanic crust in the Colombian Andes (Nivia et al 2006;Bourgois et al 1987). When compared with the Sandwich-type subduction previously analyzed, the polarity of the subduction zone is opposed.…”

Section: Rocas Verdes Basinmentioning

confidence: 77%

The tectonic regime along the Andes: Present‐day and Mesozoic regimes

Ramos¹

2009

Geological Journal

217

139

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The analyses of the main parameters controlling the present Chile-type and Marianas-type tectonic settings developed along the eastern Pacific region show four different tectonic regimes: (1) a nearly neutral regime in the Oregon subduction zone; (2) major extensional regimes as the Nicaragua subduction zone developed in continental crust; (3) a Marianas setting in the Sandwich subduction zone with ocean floored back-arc basin with a unique west-dipping subduction zone and (4) the classic and dominant Chile-type under compression. The magmatic, structural and sedimentary behaviours of these four settings are discussed to understand the past tectonic regimes in the Mesozoic Andes based on their present geological and tectonic characteristics. The evaluation of the different parameters that governed the past and present tectonic regimes indicates that absolute motion of the upper plate relative to the hotspot frame and the consequent trench roll-back velocity are the first order parameters that control the deformation. Locally, the influences of the trench fill, linked to the dominant climate in the forearc, and the age of the subducted oceanic crust, have secondary roles. Ridge collisions of seismic and seismic oceanic ridges as well as fracture zone collisions have also a local outcome, and may produce an increase in coupling that reinforces compressional deformation. Local strain variations in the past and present Andes are not related with changes in the relative convergence rate, which is less important than the absolute motion relative to the Pacific hotspot frame, or changes in the thermal state of the upper plate. Changes in the slab dip, mainly those linked to steepening subduction zones, produce significant variations in the thermal state, that are important to generate extreme deformation in the foreland.

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Section: Rocas Verdes Basinmentioning

confidence: 77%

The tectonic regime along the Andes: Present‐day and Mesozoic regimes

Ramos¹

2009

Geological Journal

217

139

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“…There is no consensus on their tectonic and geodynamic significance and they have been interpreted as related either to subduction, accretion, or collision processes (e.g. Feininger, 1980;Aspden and McCourt, 1986;Bourgois et al, 1987;Aspden et al, 1995;Lucassen et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Geodynamic significance of the Raspas Metamorphic Complex (SW Ecuador): geochemical and isotopic constraints

et al. 2002

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The Raspas Metamorphic Complex of southwestern Ecuador is regarded as the southernmost remnant of oceanic and continental terranes accreted in the latest Jurassic -Early Cretaceous. It consists of variably metamorphosed rock types. (1) Mafic and ultramafic rocks metamorphosed under high-pressure (HP) conditions (eclogite facies) show oceanic plateau affinities with flat REE chondrite-normalized patterns, eNd 150 Ma ranging from + 4.6 to 9.8 and initial Pb isotopic ratios intermediate between MORB and OIB. (2) Sedimentary rocks metamorphosed under eclogitic conditions exhibit LREE enriched patterns, strong negative Eu anomalies, Rb, Nb, U, Th, Pb enrichments, low eNd 150 Ma values (from À 6.4 to À 9.5), and high initial 87 Sr/ 86 Sr and 206,207,208 Pb/ 204 Pb isotopic ratios suggesting they were originally sediments derived from the erosion of an old continental crust. (3) Epidote-bearing amphibolites show N-MORB affinities with LREE depleted patterns, LILE, Zr, Hf and Th depletion, high eNd 150 Ma (> + 10) and low initial Pb isotopic ratios. The present-day well defined internal structure of the Raspas Metamorphic Complex seems to be inconsistent with the formerly proposed interpretation of a ''tectonic mélange''. The association of oceanic plateau rocks and continent-derived sediments both metamorphosed in HP conditions suggests that the thin edge of the oceanic plateau first entered the subduction zone and dragged sediments downward of the accretionary wedge along the Wadatti -Benioff zone. Subsequently, when its thickest part arrived into the subduction zone, the oceanic plateau jammed the subduction processes, due to its high buoyancy. In Ecuador and Colombia, the latest Jurassic -Early Cretaceous suture involves HP oceanic plateau rocks and N-MORB rocks metamorphosed under lower grades, suggesting a composite or polyphase nature for the latest Jurassic -Early Cretaceous accretionary event. D

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“…Evidences have shown [3,8,9] that oceanic crust emplacement (Figure 2) along Colombia Andes occurred through accretion (Western Cordillera), and obduction (Central Cordillera) during Upper Cretaceous-Lower Tertiary time. At two different sites i.e.…”

Section: Kinematic and Tectonic Frameworkmentioning

confidence: 99%

“…This complex area (Figure 1) is located along the southern segment of the transcontinental Dolores-Guayaquil megashear [2,3]. The Panama block and the South Caribbean Deformed Belt including the Maracaibo block bound the Northern Andes to the North.…”

Section: Introductionmentioning

confidence: 99%

A Review on Tectonic Record of Strain Buildup and Stress Release across the Andean Forearc along the Gulf of Guayaquil-Tumbes Basin (GGTB) near Ecuador-Peru Border

Bourgois¹

2013

IJG

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Gravimetric and geologic data show that the reactivation of the Neogene Interandean depression and/or the ~75 -65 Ma ophiolite suture into the modern dynamic of the Andes controlled the Gulf of Guayaquil Tumbes basin (GGTB) location and evolution during the past 1.8 -1.6 Myr at least. Depending on whether the remobilization occurred along the interandean depression or the ophiolite suture, the GGTB evolved trough pure or simple shear mechanisms, respectively. Because the GGTB exhibits an along strike tectonic asymmetry associated with a pervasive seismic gap, the simple shear solution is more likely. Tectonic inversion occurred along a mid-crust detachment (the Mid-Crust detachment hereafter) matching the ophiolite suture that accommodates the North Andean Block (NAB) northward drift. The so-called Decoupling Strip located at the shelf slope break accommodated the tensional stress rotation from N-S along the shelf area i.e. NAB-drift induced to E-W along the continental margin i.e. subduction-erosion-induced. The landward dipping Woollard detachment system located at the Upper-Lower slope boundary connects the subduction channel at depth, allowing the Upper slope to evolve independently from the Lower slope wedge. The long-term recurrence interval between earthquakes, the strong interplate coupling, and the aseismic creeping deformation acting along the main low-angle detachments i.e. the Woollard and the Mid-Crust detachments may account for the pervasive seismic gap at the GGTB area. Because the subduction channel exhibits no record of significant seismic activity, no evidence exists to establish a link between the GGTB sustained subsidence and a basin-centered asperity. Because the GGTB is a promising site of hydrocarbon resources, to understand processes at the origin of this escape-induced forearc basin has a major economic interest.

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Geological history of the Cretaceous ophiolitic complexes of northwestern South America (Colombian Andes)

Cited by 56 publications

References 15 publications

The tectonic regime along the Andes: Present‐day and Mesozoic regimes

The tectonic regime along the Andes: Present‐day and Mesozoic regimes

Geodynamic significance of the Raspas Metamorphic Complex (SW Ecuador): geochemical and isotopic constraints

A Review on Tectonic Record of Strain Buildup and Stress Release across the Andean Forearc along the Gulf of Guayaquil-Tumbes Basin (GGTB) near Ecuador-Peru Border

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