CONFIGURACIÓN DEL SEGMENTO SUR DEL OFFSHORE DE LA CUENCA DE MAGALLANES Y CUENCA DE MALVINAS, Y FAJA PLEGADA Y CORRIDA ASOCIADA, ARGENTINA

J.P. ORMAZABAL; A.A. TASSONE; F.D. ESTEBAN; J. LOZANO

Tucuman

Congreso; XX Congreso Geológico Argentino; 2017

Asociación Geológica Argentina

For this work 25.000 km of multichannel seismic sections were interpreted, together with batimetric and magnetometric data. This study is focused on the characteristics of the foredeep and wedge top belonging to these basins, between 67ºW and 62ºW. From this information, two different zones ?west and east- can be detected, and connected through a transition zone, which is characterized by a projection in the deformational front to the East.The western sector has a sharp basin profile, mainly in the foredeep, due to activity of normal faults generated from the basement; and a short wedge top, because of intense erosion. The wedge top deposits have Eocene to middle Miocene age. In contrast, the eastern sector is structured above these basement steps, promoting a gentle basin profile in the foredeep. Furthermore, this section has more thicker deposits, and younger wedge top deposits, until upper Miocene age.Basement steps were initiated as hemigrabens during the Mesozoic, and were affected later by orogenic wedge load and strike-slip. Over them, there are several anticlinals affecting Cenozoic deposits on the western section. From this, we can infer that basement steps have concentrated compressional/transpressional deformation in the area. A similar situation is inferred in the eastern section, where are steps below the frontal section of the orogenic wedge, affecting its structuring.Deformational front position, which is more advanced to the East, could be related to the difference in the efforts produced between western and eastern sections, associated to Fracture Zones and guidelines observed from Scotia Plate.