GEOLOGY AND STRUCTURE OF THE PEÑÓN BLANCO INTRUSIVE COMPLEX, DURANGO, MÉXICO

The Peñón Blanco intrusive complex is a granitic pluton with associated dikes and sills, located in the center-northeast area of Durango state, in the hinterland of the Mexican Fold and Thrust Belt. This igneous body is emplaced in the core of the Yerbanis anticline, which was generated by thin-skinned deformation (Sevier-Laramide Orogeny) during the Upper Cretaceous. According to the field evidences, the igneous body generated during the intrusion its space mainly through stopping and assimilation of the country rocks and was emplaced in dominating post-tectonic conditions after the fold development. Due its characteristics, the anticline is interpreted as a fault-bend fold, whose flanks were subsequently affected by younger normal faults related to the Basin and Ranges tectonic event.

In the studied area low sulphidation epithermal deposits have been reported, which have been dated by ⁴⁰Ar/³⁹Ar in adularia crystals, assigning them an age of 31.29±0.08 Ma (Early Oligocene; Camprubí et al., 2016). This age corresponds to the characteristic time period of the Cenozoic ore deposits in México. This post-tectonic magmatic event, developed during the Lower Oligocene after the Sevier-Laramide deformation, exhibits economically important mineralizations in the western region of the Mexican Fold and Thrust Belt.