DEEP SEISMIC DISCONTINUITY STRUCTURE BENEATH CENTRAL NEUQUEN BASIN, ARGENTINA

A singular mathematical reprocessing of old seismic lines recorded by the industry, let to illuminate the crustal structure down to about 33 km depth. An iterative depth-migration methodology guaranteed the consistency of a final model of the Crust. Important inversion events were recognized by seismic stratigraphic analysis of the basin, and dated as Pliensbachian – Torcian, and Bathonian – Callovian. Deep seismic reflectors were interpreted as the top of the lower Crust, and two important faults which controlled the rift basin geometry during its evolution. Rift basin geometry would be driven by deep ancestral discontinuities, associated with the late Triassic - early Jurassic opening of the Neuquén Basin. In such sense, a first-order crustal-diffraction attribute (about 20-33 km depth, and with east polarity) was located beneath Las Cárceles region (western foothills of Sierra de Los Chihuidos). It could be the evidence of a thermal-mechanical (extensional) collapse of an early orogen located on the Proto-Pacific continental margin of Gondwana.