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

Torres Sánchez, Sonia Alejandra y Augustsson, Carita y Jenchen, Uwe y Barboza Gudiño, José Rafael y Alemán Gallardo, Eduardo Alejandro y Ramírez Fernández, Juan Alonso y Torres Sánchez, Darío y Abratis, Michael (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. ISSN 2391-5447

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URL o página oficial: http://doi.org/10.1515/geo-2017-0029

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Abstract: 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 (1–184ppm),Pb(0.1–14ppm),andCe(0.1–1.9ppm)the rocks have mid-ocean ridge and subduction zones characteristics.TheserpentinitecontainsAl-chromite,ferrian chromiteandmagnetite.TheAl-chromiteischaracterized byCr#of0.48to0.55suggestingaMORBorigin,andCr#of 0.93 to 1.00 for the ferrian chromite indicates a prograde metamorphism.Weproposeatleasttwoserpentinization stagesoflithosphericmantlefortheultramaficrockofthe GranjenoSchist,(1)afirstinanocean-floorenvironment atsub-greenschisttogreenschistfaciesconditionsand(2) later a serpentinization phase related to the progressive replacement of spinel by ferrian chromite and magnetite atgreenschisttolowamphibolitefaciesconditionsduring regional metamorphism. The second serpentinization phase took place in an active continental margin during the Pennsylvanian. We propose that the origin of the ultramaficrocksisrelated toanobductionandaccretional eventatthewesternmarginofPangea. Keywords: ultramafic rocks; serpentinite; Granjeno Schist;northeasternMexico,Gondwana,Pangea

Tipo de elemento: Article
Palabras claves no controlados: Ultramafic rocks, Serpentinite, Granjeno Schist, Northeastern Mexico, Gondwana, Pangea
Materias: S Agricultura > SD Ciencia forestal
Divisiones: Ciencias de la Tierra
Usuario depositante: Lic. Jesús E. Alvarado
Creadores:
CreadorEmailORCID
Torres Sánchez, Sonia AlejandraNO ESPECIFICADONO ESPECIFICADO
Augustsson, CaritaNO ESPECIFICADONO ESPECIFICADO
Jenchen, UweNO ESPECIFICADONO ESPECIFICADO
Barboza Gudiño, José RafaelNO ESPECIFICADONO ESPECIFICADO
Alemán Gallardo, Eduardo AlejandroNO ESPECIFICADONO ESPECIFICADO
Ramírez Fernández, Juan AlonsoNO ESPECIFICADONO ESPECIFICADO
Torres Sánchez, DaríoNO ESPECIFICADONO ESPECIFICADO
Abratis, MichaelNO ESPECIFICADONO ESPECIFICADO
Fecha del depósito: 02 Mar 2020 16:24
Última modificación: 01 Mayo 2020 15:21
URI: http://eprints.uanl.mx/id/eprint/18249

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