Age and evolution of thin-skinned deformation in Zacatecas, Mexico: Sevier orogeny evidence in the Mexican Fold-Thrust Belt C  esar Francisco Ramírez-Pe ~ na a , Gabriel Ch  avez-Cabello b, * a Posgrado de la Facultad de Ciencias de la Tierra, Universidad Aut onoma de Nuevo Le on, Carretera a Cerro Prieto Km. 8 Ex e Hacienda de Guadalupe, Linares, N.L., A.P. 104, C.P. 67700, Mexico b Facultad de Ciencias de la Tierra, Universidad Aut onoma de Nuevo Le on, Carretera a Cerro Prieto Km. 8 Ex e Hacienda de Guadalupe, Linares, N.L., A.P. 104, C.P. 67700, Mexico article info Article history: Received 5 December 2016 Accepted 13 January 2017 Available online 18 January 2017 Keywords: Thin-skinned deformation Early Turonian-late Campanian Synorogenic sediments Syntectonic intrusives Mexican Fold-Thrust Belt abstract Integrating U-Pb ages from zircons of syn- and postectonic intrusives emplaced in folded pre- and synorogenic marine sedimentary rocks, it is proposed that thin-skinned deformation in the Concepci  on del Oro salient of the Mexican Fold Thrust Belt in northern Zacatecas, Mexico, was active between 92 and 71.6 Ma. The intrusives Pico de Teyra and El Pe~ nuelo (U-Pb zircon ages: 76.9 and 72.5 Ma) show internal tectonic foliations and horizontal shear zones that cut off aplitic veins, which apparently developed syntectonically to thin-skinned deformation. Other intrusives like Saltillito (71.6 Ma) and Concepci  on del Oro are clearly postectonic because they are undeformed internally, cut regional structures and are younger than syntectonic plutons. Biostratigraphic ages reported for synorogenic sediments (Concepci  on del Oro and Parras formations) indicate that regional thin-skinned deformation was active between Early Turonian and Late Campanian, which is in agreement with syn and post- ectonic intrusive emplacement ages in the area. Nevertheless, the thin-skinned structures are dis- rupted by a younger NNW-SSE high angle reverse and normal faults that uplifts the San Juli an Block in the west and truncate the Concepci  on del Oro salient, suggesting a post-Paleocene thick-skinned stage of deformation. In this work, we propose that style and age of thin-skinned deformation is similar to the Sevier orogeny in the Rocky Mountains. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction The Mexican Fold-Thrust Belt (MFTB) is the most prominent tectonic feature in eastern Mexico and it represents the continua- tion of the North American Rocky Mountains into mexican terri- tory. The MFTB extends for >2000 km from northern Chihuahua to Oaxaca state in southern, Mexico (Campa and Coney, 1983, Padilla y S anchez, 1982, 1985; Eguiluz de Antu~ nano et al., 2000; Fitz-Díaz et al., 2012, 2017 , Fig. 1). There is an active controversy about whether there was Sevier deformation in the MFTB or if it was produced only by the Laramide orogeny (Guzm an and de Cserna, 1963; Gray et al., 2001; Gray and Lawton, 2011). The Sevier belt in the U.S.A. is characterized by thin-skinned deformation affecting mainly Jurassic-Cretaceous sedimentary rocks and deformation occurred between 130 and 50 Ma (e.g., Dickinson et al., 1988; Yonkee, 1992; McQuarrie and Chase, 2000; Taylor et al., 2000; DeCelles et al., 1995; DeCelles, 2004; DeCelles and Coogan, 2006; Yonkee and Weil, 2015). On the other hand, the Laramide orogeny is a tectonic event that involved generation and reac- tivation of basement faults, a phenomenon that affected both the basement rocks and the upper sedimentary cover in western U.S.A. in the lapse between 75 and 40 Ma (e.g., Coney, 1976; Allmendinger et al., 1982; Dickinson et al., 1988; Lawton and Trexler, 1991). Deformation styles produced by both orogenies are contrasting and they coexist in some areas in the U.S.A. (Barth et al., 2004; DeCelles, 2004; Yonkee and Weil, 2015), where they partially overlap in age, between 75 and 50 Ma. The coexistence of these two deformation styles was recognized in the study area and has been documented in Chihuahua (Hennings, 1994), Coahuila (Ch avez-Cabello et al., 2007) and Tamaulipas (Zhou et al., 2006), Mexico. During Cretaceous time, several regions in Mexico experienced tectonic shortening at different crustal levels and areas, a defor- mation pulse that has been constrained between 115 and 40 Ma (Suter, 1984; Hausback, 1984; Aranda-G omez and P erez-Venzor, * Corresponding author. E-mail address: gabriel.chavezcbl@uanl.edu.mx (G. Ch avez-Cabello). Contents lists available at ScienceDirect Journal of South American Earth Sciences journal homepage: www.elsevier.com/locate/jsames http://dx.doi.org/10.1016/j.jsames.2017.01.007 0895-9811/© 2017 Elsevier Ltd. All rights reserved. Journal of South American Earth Sciences 76 (2017) 101e114