Skip to Main content Skip to Navigation
Book sections

Influence of the subduction of the Carnegie volcanic ridge on Ecuadorian geology: Reality and fiction

Abstract : 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.
Complete list of metadatas

https://hal-insu.archives-ouvertes.fr/insu-00406266
Contributor : Adminhal Univbrestbu <>
Submitted on : Tuesday, July 21, 2009 - 5:23:29 PM
Last modification on : Wednesday, October 14, 2020 - 4:23:22 AM

Identifiers

Citation

François Michaud, Jean-Yves Royer, César Witt. Influence of the subduction of the Carnegie volcanic ridge on Ecuadorian geology: Reality and fiction. Suzanne Mahlburg Kay, Víctor A. Ramos, and William R. Dickinson. Backbone of the Americas: Shallow Subduction, Plateau Uplift, and Ridge and Terrane Collision, Geological Society of America, pp.217-228, 2009, Geological Society of America Memoirs 204, ⟨10.1130/2009.1204(10)⟩. ⟨insu-00406266⟩

Share

Metrics

Record views

446