Título

Petrology and geochemistry of meta-ultramafic rocks in the Paleozoic Granjeno Schist, northeastern Mexico: Remnants of Pangaea ocean floor

Autor

SONIA ALEJANDRA TORRES SANCHEZ

Uwe Jenchen

JOSE RAFAEL BARBOZA GUDIÑO

JUAN ALONSO RAMIREZ FERNANDEZ

DARIO TORRES SANCHEZ

Nivel de Acceso

En Embargo

Licencia

http://creativecommons.org/licenses/by-nc-nd/4.0

Identificador alterno

doi: https://doi.org/10.1515/geo-2017-0029

Materias

Ultramafic rocks - (AUTOR) Serpentinite - (AUTOR) Granjeno Schist - (AUTOR) Northeastern Mexico - (AUTOR) Gondwana - (AUTOR) Pangea - (AUTOR) CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA - (CTI) CIENCIAS DE LA TIERRA Y DEL ESPACIO - (CTI) GEOLOGÍA - (CTI)

Resumen o descripción

"The Granjeno Schist is a meta-volcanosedimentary upper Paleozoic complex in northeastern Mexico. We suggest different tectonic settings for metamorphism of its serpentinite and talc-bearing rocks based on petrographic and geochemical compositions. According to the REE ratios (LaN/YbN = 0.51 –20.0 and LaN/SmN = 0.72–9.1) and the enrichment in the highly incompatible elements Cs (0.1 ppm), U (2.8 ppm), and Zr (60 ppm) as well as depletion in Ba (1 – 15 ppm), Sr (1 –184 ppm), Pb (0.1 –14 ppm), and Ce (0.1 –1.9 ppm) the rocks have mid-ocean ridge and subduction zones characteristics. The serpentinite contains Al-chromite, ferrian chromite and magnetite. The Al-chromite is characterized by Cr# of 0.48 to 0.55 suggesting a MORB origin, and Cr# of 0.93 to 1.00 for the ferrian chromite indicates a prograde metamorphism. We propose at least two serpentinization stages of lithospheric mantle for the ultramafic rock of the Granjeno Schist, (1) a first in an ocean-floor environment at sub-greenschist to greenschist facies conditions and (2) later a serpentinization phase related to the progressive replacement of spinel by ferrian chromite and magnetite at greenschist to low amphibolite facies conditions during regional metamorphism. The second serpentinization phase took place in an active continental margin during the Pennsylvanian. We propose that the origin of the ultramafic rocks is related to an obduction and accretional event at the western margin of Pangea."

Editor

Walter de Gruyter GmbH

Fecha de publicación

enero de 2017

Tipo de publicación

Artículo

Versión de la publicación

Versión publicada

Recurso de información

http://ipicyt.repositorioinstitucional.mx/jspui/handle/1010/1641

Formato

application/pdf

Sugerencia de citación

Torres-Sánchez, S., Augustsson, C., Jenchen, U., et al. (2017). Petrology and geochemistry of meta-ultramafic rocks in the Paleozoic Granjeno Schist, northeastern Mexico: Remnants of Pangaea ocean floor. Open Geosciences, 9(1), pp. 361-384. Retrieved 20 Aug. 2018, from doi:10.1515/geo-2017-0029

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Repositorio IPICYT

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