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Tectonic evolution of the northern Cocos plate

Several features on the Cocos plate appear to be anomalous or of unclear origin. Specifically, the eastern extension of the Orozco Fracture Zone near lat 15{degrees}N has a northeast trend, which differs significantly from the nearly east-west motion of the Pacific and Cocos plates. Moreover, the Te...

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Bibliographic Details
Published in:Geology (Boulder) 1976-12, Vol.4 (12), p.718-722
Main Authors: Lynn, Walter S, Lewis, Brian T R
Format: Article
Language:English
Online Access:Get full text
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Summary:Several features on the Cocos plate appear to be anomalous or of unclear origin. Specifically, the eastern extension of the Orozco Fracture Zone near lat 15{degrees}N has a northeast trend, which differs significantly from the nearly east-west motion of the Pacific and Cocos plates. Moreover, the Tehuantepec Ridge has a similar northeast strike and separates the deep Guatemala Basin on its southeast side from shallower crust to the northwest. The origin of these features can be adequately described by a small change in Cocos-Pacific plate motion and a 20{degrees} reorientation of the East Pacific Rise. This reorientation is strongly substantiated by a 'fanning' of magnetic anomaly lineations over the Cocos plate between the Orozco Fracture Zone and the Tehuantepec Ridge. The reconstruction assumes that the Tehuantepec Ridge is a relict fracture zone; this interpretation is supported by recent gravity models across the ridge. The Guatemala Basin is the result of older crust formed prior to a ridge-axis jump (Clipperton Ridge to East Pacific Rise) and the reorientation of the East Pacific Rise.
ISSN:0091-7613
DOI:10.1130/0091-7613(1976)42.0.CO;2