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Diversité du volcanisme miocène à quaternaire post-subduction de la péninsule de Basse Californie et du Golfe de Californie (Mexique): rôle de la déchirure de la plaque Farallon

Abstract : The geological history of the Baja California peninsula and the Gulf of California is entirely related to the evolution of the North America plate Western margin during the last 80 Ma. Two main geological episodes are registered (i) during the Middle Mesozoic when the Farallon-Kula plate sunk by subduction along the western coast of North America, and (ii) during the Middle Cenozoic when a new magmatic activity appeared, it emplaced calc-alkaline lavas of Comondu arc. Neogene magmatic activity in Central Baja California underwent a major change at around 12.5 Ma. Comondu calc-alkaline magmatism vanished and was replaced by unusual volcanic associations linked to asthenospheric window. Several Neogene to Quaternary petrological and geochemical groups were identified in the Baja California volcanic fields: (i) calc-alkaline lavas, (ii) adakites, (iii) adakites and niobium-enriched basalts (NEB), (iv) tholeiitic basalts and basaltic andesites and MORB type tholeiites, (v) basalts and associated magnesian basaltic andesites and andesites (“bajaites”) and (vi) OIB type alkali trachybasalts. We propose that the emplacement of slab window-related volcanic rocks between 13 and 7 Ma was due to a process of slab tearing of Farallon plate, which started from the southern limit of the already existing Southern California slab window.
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https://tel.archives-ouvertes.fr/tel-00180274
Contributor : Carlos Pallares <>
Submitted on : Thursday, October 18, 2007 - 3:07:25 PM
Last modification on : Wednesday, September 16, 2020 - 9:56:41 AM
Long-term archiving on: : Sunday, April 11, 2010 - 11:15:00 PM

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  • HAL Id : tel-00180274, version 1

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Carlos Pallares. Diversité du volcanisme miocène à quaternaire post-subduction de la péninsule de Basse Californie et du Golfe de Californie (Mexique): rôle de la déchirure de la plaque Farallon. Géologie appliquée. Université de Bretagne occidentale - Brest, 2007. Français. ⟨tel-00180274⟩

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