Concurrence of folding and remagnetization events in the Monterrey Salient (NE Mexico)
Por:
Nemkin, Samantha R., Chavez-Cabello, Gabriel, Fitz-Diaz, Elisa, van der Pluijm, Ben, Van der Voo, Rob
Publicada:
1 ene 2019
Resumen:
Carbonate formations from many locations reveal magnetizations that are secondary. Attaching a numerical age to these remagnetizations would provide information on orogenic processes. To contribute to the effort of assigning an age to remagnetization events, Lower Cretaceous formations from the Monterrey Salient in northeast Mexico were sampled. Individual fold tests reveal eight site-pair synfolding remagnetizations (set A) of Eocene age. The remanence is a chemical remanent magnetization (CRM) carried by magnetite. The magnetization of set B is possibly due to an early carbonate alteration that produced a remanence significantly older than folding. A complexity of set B is that the site pairs reveal k-versus-unfolding percentage diagrams with maximum unfolding peaks at 100 to 125%. An explanation of multiple deformation phases with an earlier horizontal folding phase around a non-plunging horizontal axis and a later vertical axis rotation is suggested for the past 100% peaks of the B sites. The latter deformation, rotation about a vertical axes, is revealed by a declination-strike test in set A sites and site means of the full collection that deviate counterclockwise from the reference declination. By combining synfolding results with published 40 Ar/ 39 Ar illite ages of folding (Fitz-Diaz et al., 2016), remagnetization ages in set A sites of 48–52 Ma are obtained. The magnetization in set B sites is likely older, though not well constrained. Interestingly, prior results from the central Sierra Madre Oriental, to the south, show two remagnetization events, Late Cretaceous and Early Eocene in age, in a succession from W to E (Nemkin et al., 2015). The age of folding and remagnetization acquisition in set A sites along the Monterrey Salient are concurrent with the frontal, remagnetized folds in the central Sierra Madre Oriental. Thus, the timing of major remagnetization in the Monterrey Salient occurred in the Eocene. © 2017 Elsevier B.V.
Filiaciones:
Nemkin, Samantha R.:
Department of Earth & Environmental Sciences, University of Michigan, Ann Arbor, MI, United States
Univ Michigan, Dept Earth & Environm Sci, Ann Arbor, MI 48109 USA
Chavez-Cabello, Gabriel:
Universidad Autónoma de Nuevo León, Facultad de Ciencias de la Tierra, Linares, N.L. C.P. 67700, Mexico
Univ Autonoma Nuevo Leon, Fac Ciencias Tierra, Linares 67700, NL, Mexico
Fitz-Diaz, Elisa:
Instituto de Geología, Universidad Nacional Autónoma de México Ciudad Universitaria, CDMX, 04510, Mexico
Univ Nacl Autonoma Mexico, Inst Geol, Ciudad Univ, Cdmx 04510, DF, Mexico
van der Pluijm, Ben:
Department of Earth & Environmental Sciences, University of Michigan, Ann Arbor, MI, United States
Univ Michigan, Dept Earth & Environm Sci, Ann Arbor, MI 48109 USA
Van der Voo, Rob:
Department of Earth & Environmental Sciences, University of Michigan, Ann Arbor, MI, United States
Univ Michigan, Dept Earth & Environm Sci, Ann Arbor, MI 48109 USA
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