Análisis estructural del proyecto de skarn Fermín

GIAMBIAGI L

2022-02-01

2022-06-01

Rec.Nat.No Renov.-Minerales metalicos

The Fermin area lies inside a broad zone of contractional deformation that was tectonically active at the time of the skarn formation.● Skarn deposits are affected by at least two deformational events: (a) a brittle-ductile deformational event with WSW contraction, and related to folds and thrusts; and (b) a brittle strike-slip event with conjugated NE-to-NNE dextral and WNW-to-NW sinistral fault systems. The first one corresponds to the older event, and it is assigned here to the late Early Permian (San Rafael orogeny). During this stage, limestones behave under a ductile regime and develop non-parallel folding, but the volcaniclastic and volcanic rocks deform under a brittle regime and develop only parallel folding. Moreover, at outcrop, there is a close association of recumbent folds and mostly east-vergent thrusts. This indicates that the deforming rocks were located inside the upper crust, at the brittle/ductile transition.Contractional faults only affect Permian volcanic layers, and they are assigned here to the San Rafael orogeny. Contractional axes obtained for these faults are highly variable, ranging from NW to SW, suggesting later rotations along vertical axes that we assume may have happened during the late Miocene-early Pliocene strike-slip event. The strike-slip fault system affects the upper Miocene volcanic and volcaniclastic rocks, as well as the older ones, and it is assigned here to a late Miocene-early Pliocene event. The kinematic analysis of meso-scale faults indicates WSW contraction and NNW extension, responsible for the development of a conjugate system of NW sinistral faults and NE dextral faults.