Meso-Neoproterozoic basic-intermediate mafic granulites (metabasites) from the ∼1 Ga granulitic southwestern Oaxacan complex, Mexico, crustal evolution and phase equilibria modeling
Culí i Verdaguer, Laura (Universitat Autònoma de Barcelona. Departament de Geologia)
Reche Estrada, Joan (Universitat Autònoma de Barcelona. Departament de Geologia)
Solé, Jesús (Universidad Nacional Autónoma de México. Instituto de Geología)
Ortega-Gutiérrez, Fernando (Universidad Nacional Autónoma de México. Instituto de Geología)

Data:	2023
Resum:	The basement of eastern Mexico is made up of Grenvillian granulite-facies metamorphic rocks, which constitute an inferred microcontinent named Oaxaquia. Proto-Oaxaquia oceanic arc reconstructions are related to the transition from Columbia to Rodinia supercontinents (∼1. 5 Ga). This study focuses on the petrography, geochemistry, and phase equilibria modeling of metabasites from the southwestern Oaxacan Complex, the largest Oaxaquia outcrop. Southwestern Oaxacan Complex protoliths mainly correspond to gabbro/basalt. They constitute an assemblage apart from the rest of the Oaxacan Complex metabasites due to their Ti enrichment and SiO2 depletion related to post-magmatic/metamorphic processes. Southern study site metabasites correspond to the primitive root of the arc, mostly related to a divergent geotectonic setting. The other metabasites are related to the magmatic back/forearc active margin between proto-Oaxaquia and Amazonia craton. Phase equilibria modeling point to Zapotecan (last Grenvillian cycle) metamorphic peak conditions of 850 ± 25 °C and 1. 0 ± 0. 15 GPa from one garnet-amphibole bearing metabasite, and a later hydration episode (post-Grenvillian) of 760 ± 10 °C and 0. 8 ± 0. 20 GPa derived from one amphibole bearing metabasite. The time of incipient partial melting of the southwestern Oaxacan Complex is a pre-Zapotecan event (∼1 Ga). Mineral textures do not display significant processes related to the post-Zapotecan metamorphic retrogression, and only a few whole-rock light rare element patterns display strong enrichments.
Ajuts:	Agencia Estatal de Investigación PID2019-109018RB-I00 Ministerio de Economía y Competitividad 2015-66335-C2-2-R
Nota:	Altres ajuts: acords transformatius de la UAB
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Grenvillian orogen ; Island/magmatic arc ; Metabasite geochemistry ; Partial melting ; Restite ; Southwestern Oaxacan complex
Publicat a:	Lithos, Vol. 454-455 (October 2023) , art. 107239, ISSN 1872-6143

DOI: 10.1016/j.lithos.2023.107239

18 p, 19.9 MB

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