Abstract

CHAVEZ CABELLO, Gabriel et al. Structural evolution of the tectonic from of the Sierra Madre Oriental at the Santa Rosa canyon, Linares, N.L.. Bol. Soc. Geol. Mex [online]. 2011, vol.63, n.2, pp.253-270. ISSN 1405-3322.

The software 2D Move (v. 5.1) was used to perform the structural restoration (inverse deformation modeling) of the folds and thrust faults exposed at the Santa Rosa Canyon, southwest of Linares (Nuevo León) in the leading edge of the Sierra Madre Oriental (SMO) thrust and fold belt. Based on detailed mapping we recognized four important faults in the study area: (a) the youngest fault is a structure that propagated from the basement and altered the structural relief between the trailing portion of the structures and the range front of the SMO, (b) a secondary reverse fault in the Santa Rosa bridge area, which thrusts Lower Cretaceous against Upper Cretaceous rocks, (c) the main thrust, which has at least 1900 m of structural displacement, and juxtaposes Upper Jurassic atop Upper Cretaceous rocks, and lastly, (d) a left-lateral strike-slip fault that cross-cut and displaces nearly 2000 m older structures, such as the hinge zone of the Jaures anticline and the frontal thrust of the SMO in the area. The structural restoration allowed us to infer the existence of early detachment folds that grew from a weak layer composed by Upper Jurassic evaporites. We interpret that the detachment folds altered their original geometry as regional shortening increased; thrusting their frontal limbs as a propagating fault and, finally, the structure was transported through the fault and acquired ramp geometry. Using the geometric features of the structures, a minimum shortening of 37 % was estimated in the zone with tectonic transport to the east-northeast.

Keywords : Sierra Madre Oriental; thrust fault; structural restoration; 2D Move; Santa Rosa canyon; detachment folds.

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