Cross-strike structures controlling magmatism emplacement in a flat-slab setting (Precordillera, Central Andes of Argentina)

Abstract

Detailed structural, kinematic and geophysical data on the foreland of the Pampean flat-slab segment (Hualilán area, Andean Precordillera of Argentina) have shown that cross-strike structures have had an important role in the evolution of this Andean segment since Miocene times. These structures represent pre-existing crustal fabrics reactivated during the Andean orogeny and could have controlled the emplacement of the Miocene arc-magmatism migrating into foreland due to the flattening of the slab. Likewise, kinematic results obtained for these structures support a similar stress frame to that obtained elsewhere in the Precordillera but showing different motions as a consequence of their high obliquity to the orogen trend. Moreover, they record a reorientation of kinematic axes during Late Miocene–Pliocene times.