Structure of the wedge-top and foredeep of the Magallanes-Malvinas basins between 62° W and 67° W (SW Atlantic Ocean)

ORMAZABAL, JUAN PABLO; ISOLA, JOSÉ; MENICHETTI, MARCO; TASSONE, ALEJANDRO; CAYO, LUBIN ERIC; LODOLO, EMANUELE; TASSONE, ALEJANDRO; CAYO, LUBIN ERIC; LODOLO, EMANUELE; ESTEBAN, FEDERICO; LOZANO, JORGE; ESTEBAN, FEDERICO; LOZANO, JORGE; ORMAZABAL, JUAN PABLO; ISOLA, JOSÉ; MENICHETTI, MARCO

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2019 vol. 93 p. 364 - 381

0895-9811

This work analyzes the geometry and geodynamic development of the offshore sector (between 62° W and 67° W) of the south Magallanes and Malvinas basinswedge-top and foredeep, and associated orogenic wedge. It is based on the interpretation of more than 20,000 km of multichannel seismic profiles, along withbathymetric data. The fold-and-thrust belt front was mapped, and three structural domains were distinguished: western, transitional and eastern. A stepped foredeepcharacterizes the western domain with flower-structures that affect the basement, and by an intense erosion in the Miocene deposits. Towards the transitionaldomain, the erosion is less evident, and the wedge-top is more developed. This configuration is associated with the syn-deformational deposition and the generationof thrusts within an acoustically chaotic body in the transitional and eastern domains, deposited by processes of mass removal in the Oligocene. During theOligocene/Miocene, the area was affected by compression/transpression, which generated an incipient tectonic inversion of the basement extensional faults, with theformation of anticlines associated with piggy-back basins in the wedge-top. The differences observed between the western and eastern domains would be related tothe differential movement between the crustal blocks of Tierra del Fuego and Burdwood Bank, respectively, against the South American shelf since the Oligocene.