Backbone of the Americas: Shallow Subduction, Plateau Uplift, and Ridge and Terrane Collision
Influence of the subduction of the Carnegie volcanic ridge on Ecuadorian geology: Reality and fiction
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Published:June 01, 2009
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CiteCitation
François Michaud, Cesar Witt, Jean-Yves Royer, 2009. "Influence of the subduction of the Carnegie volcanic ridge on Ecuadorian geology: Reality and fiction", Backbone of the Americas: Shallow Subduction, Plateau Uplift, and Ridge and Terrane Collision, Suzanne Mahlburg Kay, Víctor A. Ramos, William R. Dickinson
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The proposed ages for the collision of the Carnegie Ridge with the South America trench, offshore Ecuador, range from 1 to 15 Ma. In this time frame, many geological features of Ecuador are commonly linked to the subduction of the Carnegie Ridge. (1) After the ridge collided with the trench at ca. 15 Ma, the subsequent interplate coupling produced high exhumation rates of volcanic materials at ca. 9 Ma. (2) The oblique convergence of the Carnegie Ridge would have caused the northward drift of the North Andean block and the opening of the Gulf of Guayaquil. (3) During the late Miocene, the subduction of the Carnegie Ridge would have triggered a regional tectonic inversion along the forearc. (4) Along the collision front of the ridge with the trench, subduction-related erosion is occurring, and the Ecuadorian continental margin is being uplifted in the present day. (5) The chemistry of the active volcanic arc is explained as resulting from the arrival of the Carnegie Ridge into the trench. For instance, the adakitic signal, which appears at 1.5 Ma, is thought to be ridge-induced. (6) The buoyancy of the subducted Carnegie Ridge would explain the flatness of the slab beneath Ecuador. In this paper, we review the geological evolution of the Northern Andes in order to establish which of these geological events may be related to the subduction of the Carnegie Ridge. This review suggests that there is no clear deformation linked with the subduction of the Carnegie Ridge or with its landward prolongation postulated at depth.
- adakites
- Andes
- basins
- body waves
- buoyancy
- Carnegie Ridge
- continental margin
- continental slope
- East Pacific
- Ecuador
- elastic waves
- exhumation
- fore-arc basins
- geochemistry
- igneous rocks
- inversion tectonics
- island arcs
- kinematics
- mid-ocean ridges
- ocean floors
- P-waves
- Pacific Ocean
- plate collision
- plate tectonics
- seismic waves
- South America
- subduction
- subduction zones
- tectonics
- trenches
- uplifts
- volcanic rocks
- volcanism
- Gulf of Guayaquil