Wrenh tectonics in the Tierra del Fuego Island (Argentina). Analysis from field and remote sensing data

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

Dead Sea

Conferencia; The first Stephan Mueller Conference of the European Geophysical Society (EGS): From continental breakup to collision; 2000

Eur2000. EGS

The Tierra del Fuego Island - the southern tip of the South America - is the supposed locus of the present-day westernmost part the South America-Scotia plate boundary, and is represented by a mainly wrench lineament, running from the western sector of the North Scotia Ridge to the Chile Trench south 50°S. The tectonic setting and the Cenozoic evolution development of this plate boundary are still mostly speculative, , because the lack of reliable geological data. Recent integration of newly acquired geophysical and geological data onshore, and along the Atlantic coast of the Island, combined with SAR images, SPOT maps and aerial photographs, have allowed to better identify the geological framework of this plate boundary. A Cretaceous–Cenozoic stratigraphic succession consisting of more than 7000m-thick siliciclastic sediments arranged in a foreland basin, is affected by sinistral wrench tectonism, which displays several step structures, at different scale, with presence of restricted pull-apart basins, N-verging fold-and-thrust belts, and splay structures related to N-S-trending faults. The main shear zones, forming part of the E-W left-lateral strike-slip Magallanes-Fagnano fault system, was identified in the field along part of the northern shore of the Lago Fagnano, where the outcropping rocks are strongly deformed and metamorphosed, and on the seismic reflection profiles acquired off the Atlantic coast of the Tierra del Fuego Island, where a noticeable fault-controlled basin was found.