Plate Motions in the north Andean region

Freymueller, J. T.; Kellogg, James N.; Vega, Victor

doi:10.1029/93jb00520

Cited by 157 publications

(89 citation statements)

References 39 publications

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“…The full spreading rate at 90 ‡W is 60 þ 4 km/m.y., using the global plate model NUVEL-1A [51], or 66 þ 4 km/m.y., from GPS measurements [38]. Magnetic anomalies suggest that sea£oor spreading along the CNSC has been roughly symmetric though slightly variable during the last 20 m.y.…”

Section: Tectonic Settingmentioning

confidence: 96%

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Crustal thickness constraints on the geodynamic evolution of the Galapagos Volcanic Province

Sallarès

Charvis

2003

Earth and Planetary Science Letters

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We developed a simple quantitative framework based on crustal thickness estimations along the Carnegie, Cocos and Malpelo ridges, to place first-order constraints on the tectonic evolution of the Galapagos Volcanic Province and on the along-axis intensity of the Galapagos melt anomaly during the last 20 m.y. Our results suggest that the CocosN azca spreading centre has migrated northwards at 26 þ 4 km/m.y. with respect to the Galapagos hotspot (GHS) during this period of time. At V20 m.y., the GHS was approximately ridge-centered, and thus the along-axis intensity of the melt anomaly at this time was the maximum. At V11.5 m.y. the hotspot was located 106 þ 27 km north of the spreading center, and the along-axis intensity of the melt anomaly was 0.54 þ 0.04 of that estimated at 20 Ma. At present day it is located at V190 km south of the spreading center and the along-axis intensity is only 0.19 þ 0.03 of that estimated at 20 Ma. These results are used to reconstruct the relative position between the GHS and the CocosN azca Spreading Center. The spreading center passed over the GHS for the last time at 7.4 þ 1.3 Ma. The Panama fracture zone was initiated at 8.9 þ 1.6 Ma, leading to the separation between the Cocos and Malpelo ridges. The present configuration of the Galapagos Volcanic Province and the plate velocities are consistent with symmetric spreading with a mean full spreading rate of V60 km/m.y. along the CNSC during the last 20 m.y. A melt flux for excess crustal production of 9.4 þ 5.1 m 3 /s is obtained for the Galapagos melt anomaly at 20 Ma, implying that the maximum potential intensity of the Galapagos plume is similar to that of the Icelandic plume and twice smaller than the Hawaiian one. ß

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Section: Tectonic Settingmentioning

confidence: 96%

“…with a trend of VN41 ‡E, and that the Nazca plate subducts almost perpendicularly beneath South America at V58 km/m.y. with respect to the stable South American craton [38,40]. The age of the Cocos Ridge subducting at the trench is v 14.5 m.y.…”

Section: Tectonic Settingmentioning

confidence: 99%

Crustal thickness constraints on the geodynamic evolution of the Galapagos Volcanic Province

Sallarès

Charvis

2003

Earth and Planetary Science Letters

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“…Indeed, the analysis of Industrial seismic lines has documented that the ~1 cm·yr −1 northward migration rate of the NAB [2,5,27] was at the origin of trench-parallel tensional stress that has controlled subsidence and GGTB formation.…”

Section: Geological Frameworkmentioning

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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“…Due to the northward component of the oceanic convergence in Late Cretaceous and Tertiary times (Pardo-Casas and Molnar, 1987) and to the evidences of large-scale dextral strike-slip movements of Tertiary age in northwestern South America (Freymuller et al, 1993), remnants of Jurassic oceanic terranes, possibly equivalent to the Raspas mafic rocks, must be sought in the northern Andes and around the Caribbean plate.…”

Section: Comparison With the Northern Andes And Caribbeanmentioning

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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Plate Motions in the north Andean region

Cited by 157 publications

References 39 publications

Crustal thickness constraints on the geodynamic evolution of the Galapagos Volcanic Province

Crustal thickness constraints on the geodynamic evolution of the Galapagos Volcanic Province

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

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

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