Sinestral Rotation and NNW Shortening of the Ambato Block induced by Cenozoic NE to E-W Transpression, Argentina

GUTIERREZ, ADOLFO ANTONIO; MON, RICARDO; ARNOUS, AHMAD; CISTERNA, CLARA EUGENIA

International Journal of Earth Science and Geology

Madridge publisher

Año: 2019 vol. 1 p. 74 - 85

South of 27° S, where the Nazca plate sinks with low angle below the South Americanplate, the mountain ranges that constitute the Sierras Pampeanas where uplifted byreverse faults, tilted to the east, during the Pliocene. The analysis and interpretation ofsatellite images and the systematic recording of fracture planes in outcrops ofmetamorphic basement rocks and Neogene sediments allow us to determine tectonicevents that gave the region of the Ambato Block a NE shortening, a sinestral rotationand NNW shortening. As a result of these tectonic events, during the convergence ofthe Nazca and South American plates, reverse faults, gravitational faults and transcurrentfaults were generated, and the division of the Ambato Block into smaller ranges and thedevelopment of intramontane basins ocurred. The Las Cañas normal fault, with E-Wstrike, was generated before the Andean tectonics, using the schistosity planes of themetamorphic basement; it constitutes a step in which the outcrops of the Santa BárbaraSubgroup of the Salta Group end.