Volcanic sequence in Late Triassic – Jurassicsiliciclastic and evaporitic rocks from Galeana, NE Mexico

Authors

  • E.M. CRUZ-GÁMEZ Universidad Autónoma de Nuevo León, Facultad de Ciencias de la Tierra Ex – Hacienda de Guadalupe, Carretera Linares – Cerro Prieto km. 8, Linares, Nuevo León67700, México.
  • F. VELASCO-TAPIA Universidad Autónoma de Nuevo León, Facultad de Ciencias de la Tierra Ex – Hacienda de Guadalupe, Carretera Linares – Cerro Prieto km. 8, Linares, Nuevo León67700, México.
  • J.A. RAMÍREZ-FERNÁNDEZ Universidad Autónoma de Nuevo León, Facultad de Ciencias de la Tierra Ex – Hacienda de Guadalupe, Carretera Linares – Cerro Prieto km. 8, Linares, Nuevo León67700, México.
  • U. JENCHEN Universidad Autónoma de Nuevo León, Facultad de Ciencias de la Tierra Ex – Hacienda de Guadalupe, Carretera Linares – Cerro Prieto km. 8, Linares, Nuevo León67700, México.
  • P. RODRÍGUEZ-SAAVEDRA Universidad Autónoma de Nuevo León, Facultad de Ciencias de la Tierra Ex – Hacienda de Guadalupe, Carretera Linares – Cerro Prieto km. 8, Linares, Nuevo León67700, México.
  • A.A. RODRÍGUEZ-DÍAZ Universidad Nacional Autónoma de México, Instituto de Geofísica Ciudad Universitaria, Delegación Coyoacán, Ciudad de México, Distrito Federal 04510, México
  • A. IRIONDO Universidad Nacional Autónoma de México, Centro de Geociencias Blvd. Juriquilla No. 3001, Querétaro, Querétaro 76230, México

Keywords:

Northeastern Mexico, island arc, continental arc, Late Triassic, Jurassic

Abstract

In northeastern Mexico, volcanic rocks interbedded with Late Triassic–Jurassic siliciclastic and evaporitic strata have been linked to magmatic arcs developed in the Pangea western margin during its initial phase of fragmentation. This work provides new petrographic and geochemical data for volcanism included in the El Alamar and Minas Viejas formations outcropping in the Galeana region. Andesitic dykes and sills (n= 10) in the El Alamar redbeds show SiO2= 47.5–59.1% and MgO= 1.2–4.2%, as well as a geochemical affinity to island arc magmas. This work represents the first report of this tectonic setting in the region. Geological and petrographic evidence suggest that this arc system likely developed after ~220 and before ~193Ma. Trachy-andesitic and rhyodacitic domes (n= 20) associated with the Minas Viejas gypsum-carbonates sequence show SiO2= 61.8–82.7% and MgO= 0.1–4.0% with a tectonic affinity to continental arc. A rhyodacite sample from this region has been dated by U-Pb in zircon, yielding an age of 149.4 ± 1.2Ma (n= 21), being the youngest age related to this arc. Finally, we propose a threestep model to explain the tectonic evolution from Late Triassic island arc to Jurassic continental arc system in the northeastern Mexico.

Author Biography

E.M. CRUZ-GÁMEZ, Universidad Autónoma de Nuevo León, Facultad de Ciencias de la Tierra Ex – Hacienda de Guadalupe, Carretera Linares – Cerro Prieto km. 8, Linares, Nuevo León67700, México.

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Published

2017-06-13

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