Structural setting of the western South America-Scotia plate boundary

ESTEBAN, F.; TASSONE, A.; LODOLO E.; MENICHETTI, M.

Granada

Conferencia; The Scotia Arc: Geodynamic Evolution & Global Implications; 2013

Instituto Andaluz de Ciencias de la Tierra

New multichannel seismic reflection data, combined with geophysical data (bathymetry and gravimetry) have imaged the morpho-structural western segment (between 66° and 56° W) of the South America-Scotia plate boundary. We have identified different transtensional (asymmetric pull-apart basins, normal faults) and transpressional structures (folds and inverse faults) associated to the plate boundary. The distribution of these structures define two main domains: (1) a western domain: it corresponds to the offshore extension of the Magallanes-Fagnano fault system, with an E-NE orientation and characterized by pull-apart basins with negative flower structures, filled with Neogene sediments; (2) an eastern domain: it is located just north of the Burdwood Bank over the Malvinas trough and is characterized by compressive Andean structures. The distribution of these two domains is primarily controlled by the rigidity of the Burdwood Bank and the weak zone related to the Magallanes-Fagnano fault system.