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Origin of the modern Chiapanecan volcanic arc in southern Mexico inferred from thermal models

Vlad C. Manea and Marina Manea
Origin of the modern Chiapanecan volcanic arc in southern Mexico inferred from thermal models (in Volcanic hazards in Central America, William I. Rose (editor), Gregg J. S. Bluth (editor), Michael J. Carr (editor), John W. Ewert (editor), Lina C. Patino (editor) and James W. Vallence (editor))
Special Paper - Geological Society of America (2006) 412: 27-38

Abstract

In southern Mexico, the subducting Cocos slab drastically changes its geometry: from a flat slab in central Mexico to a approximately 45 degrees dip angle beneath Chiapas. Also, the currently active volcanic arc, the modern Chiapanecan volcanic arc, is oblique and situated far inland from the Middle America trench, where the slab depth is approximately 200 km. In contrast, the Central America volcanic arc is parallel to the Middle America trench, and the slab depth is approximately 100 km. A two-dimensional steady-state thermomechanical model explains the calc-alkaline volcanism by high temperature ( approximately 1300 degrees C) in the mantle wedge just beneath the Central America volcanic arc and the strong dehydration ( approximately 5 wt%) of the Cocos slab. In contrast, the thermal model for the modern Chiapanecan volcanic arc shows high P-T conditions beneath the coast where the extinct Miocene Chiapanecan arc is present, and is therefore unable to offer a reasonable explanation for the origin of the modern Chiapanecan volcanic arc. We propose a model in which the origin of the modern Chiapanecan volcanic arc is related to the space-time evolution of the Cocos slab in central Mexico. The initiation of flat subduction in central Mexico in the middle Miocene would have generated a hot mantle wedge inflow from NW to SE, generating the new modern Chiapanecan volcanic arc. Because of the contact between the hot mantle wedge beneath Chiapas and the proximity of a newly formed cold, flat slab, the previous hot mantle wedge in Chiapas became colder in time, finally leading to the extinction of the Miocene Chiapanecan volcanic arc. The position and the distinct K-alkaline volcanism at El Chichon volcano are proposed to be related to the arrival of the highly serpentinized Tehuantepec Ridge beneath the modern Chiapanecan volcanic arc. The deserpentinization of Tehuantepec Ridge would have released significant amounts of water into the overlying mantle, therefore favoring vigorous melting of the mantle wedge and probably of the slab.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 412
Title: Origin of the modern Chiapanecan volcanic arc in southern Mexico inferred from thermal models
Title: Volcanic hazards in Central America
Author(s): Manea, Vlad C.Manea, Marina
Author(s): Rose, William I.editor
Author(s): Bluth, Gregg J. S.editor
Author(s): Carr, Michael J.editor
Author(s): Ewert, John W.editor
Author(s): Patino, Lina C.editor
Author(s): Vallence, James W.editor
Affiliation: California Institute of Technology, Seismological Laboratory, Pasadena, CA, United States
Affiliation: Michigan Technological University, Department of Geological Engineering and Sciences, Houghton, MI, United States
Pages: 27-38
Published: 2006
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 30
Accession Number: 2007-020892
Categories: Environmental geologySolid-earth geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. geol. sketch maps
N14°31'60" - N18°00'00", W94°10'00" - W90°19'60"
Secondary Affiliation: Rutgers University, USA, United StatesU. S. Geological Survey, USA, United StatesMichigan State University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 200712
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