Morphology and magnetic survey of the Rivera-Cocos plate boundary of Colima, Mexico

Morphology and magnetic survey of the Rivera-Cocos plate boundary of Colima, Mexico

The propagation of the Pacific-Cocos Segment of the East Pacific Rise (EPR-PCS) has significantly altered the plate configuration at the north end of the Middle America Trench. This ridge propagation, the collision of the EPR-PCS with the Middle America Trench, the separation of the Rivera and Cocos...

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Journal Title: Geofísica Internacional
First author: Juan Ramón Peláez Gaviria
Other Authors: Carlos A. Mortera Gutiérrez;
William L. Bandy;
François Michaud
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Language: English
Get full text: http://ojs.geofisica.unam.mx/ojs6/index.php/RGI/article/view/1524
Resource type: Journal Article
Source: Geofísica Internacional; Vol 52, No 1 (Year 2013).
DOI: http://dx.doi.org/10.22201/igf.00167169p.2013.1.1524
Publisher: Universidad Nacional Autónoma de México
Usage rights: Reconocimiento - NoComercial - SinObraDerivada (by-nc-nd)
Categories: Physical/Engineering Sciences --> Geochemistry --AMP-- Geophysics
Abstract: The propagation of the Pacific-Cocos Segment of the East Pacific Rise (EPR-PCS) has significantly altered the plate configuration at the north end of the Middle America Trench. This ridge propagation, the collision of the EPR-PCS with the Middle America Trench, the separation of the Rivera and Cocos plates and the formation of the Rivera Transform have produced a complex arrangement of morphotectonic elements in the area of Rivera-Cocos plate boundary, atypical of an oceanic transform boundary. Existing marine magnetic and bathymetric data has proved inadequate to unravel this complexity, thus, a dense grid of total field magnetic data were collected during campaigns MARTIC-04 and MARTIC-05 of the B/O EL PUMA in 2004 and 2006. These data have greatly clarified the magnetic lineation pattern adjacent to the Middle America trench, and have revealed an interesting en echelon, NE-SW oriented magnetic high offshore of the Manzanillo Graben. We interpret these new data to indicate that the EPR-PCS ridge segment reached the latitude (~18.3ºN) ofthe present day Rivera Transform at about Chron 2A3 (~3.5Ma) and propagated further northward, intersecting the Middle America Trench at about 1.7 Ma (Chron 2). At 1.5 Ma spreading ceased along the EPR north of 18.3ºN and the EPR-PCS has since retreated southward in association with a southward propagation of the MoctezumaSpreading Segment. North of 18.3ºN the seafloor near the trench has been broken into small, uplifted blocks, perhaps due to the subduction of the young lithosphere generated by the EPR-PCS.