Birth of an intraoceanic spreading center.

Barckhausen, Udo, Ranero, Cesar, Cande, Steven C., Engels, Martin and Weinrebe, Reimer Wilhelm (2008) Birth of an intraoceanic spreading center. Geology, 36 (10). pp. 767-770. DOI 10.1130/G25056A.1.

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Abstract

The Cocos-Nazca spreading center is one of the few examples of the formation of a spreading center by splitting of oceanic lithosphere. It was created when the Farallon plate broke up in the early Miocene following the collision of the Pacific-Farallon spreading center with the North American continent. Much of the ancient Farallon plate corresponding to the area of opening is lost to subduction beneath Central America and South America, but new data from the conjugate area on the Pacific plate allow the first detailed reconstruction of the break-up process. The opening began after chron 7 (25 Ma) at a location of focused crustal extension caused by overlapping spreading centers that had evolved in response to a slight reorientation of a Pacific-Farallon ridge segment. Beginning at chron 6B (22.7 Ma), eastward progressing seafloor spreading started along an axis that most likely migrated toward the region of weak lithosphere created by the Galapagos hotspot. By chron 6 (19.5 Ma), plate splitting from the spreading center to the trench was complete, allowing the fully detached Cocos and Nazca plates to move independently. This kinematic change resulted in a significant ridge jump of the newly established Pacific-Nazca spreading center, a change in plate motion direction of the Nazca plate by 20° clockwise, and a large increase in Pacific-Cocos plate velocity in the middle Miocene.

Document Type: Article
Keywords: Farallon breakup, Galapagos hotspot, magnetic anomalies, central Pacific
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1130/G25056A.1
ISSN: 0091-7613
Expeditions/Models/Experiments:
Date Deposited: 03 Dec 2008 16:52
Last Modified: 24 May 2017 08:25
URI: http://oceanrep.geomar.de/id/eprint/7137

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