An analogue model of a crustal-scale fracture zone in West-Central Mexico: evidence for a possible control of ore-forming processes

This paper presents the results of a study of analogue modeling of a large-scale fracture zone in west central Mexico. The fracture zone strikes perpendicular to the magmatic arc and to arc-parallel tectonic features. It is thought to have been formed during the Cretaceous-Tertiary contractional Laramide deformation, when the development of the fold-and-thrust belt was influenced by basement topography and the extent of low-friction strata (evaporites) in the basal sequences. Both factors affected the arcuate shape of the fold-and-thrust belt (Torreon-Monterrey salient) and produced a zone of structural discontinuity in the form of a fracture zone separating distinct segments of the fold-and-thrust belt. Results of sandbox analogue experiments are reported that provide first insights into how basement topography and spatial variations in basal friction affect the development of an arcuate fold-and-thrust belt and the formation of transverse fracture zones. Their later reactivation is thought to have favoured the ascent of magmas as well as the formation of secondary porosity and permeability, facilitating the circulation of hydrothermal fluids, likely controlling the location of important ore deposits.