Morphostructure of the central-eastern Tierra del Fuego Island from geological data and remote-sensing images.

LODOLO E.; MENICHETTI, M.; TASSONE, A.; STERZAI, P.

Stephan Mueller Special Publication Series

European Geophysical Society (EGS).

Año: 2002 vol. 2 p. 1 - 16

Field geological reconnaissance, combined with SPOT maps and Synthetic Aperture Radar images, provide new views on the structural and morphological framework of the Tierra del Fuego Island, the southernmost tip of the South America continent. The remote-sensing maps reveal with unprecedented detail the geological elements identified in the field, which are characterized by a noticeable morphological expression, and have allowed to reconstruct at a regional scale, the morphostructure of the central and eastern part of the Island. A system of ESE-WNW-trending asymmetric folds and associated N-verging thrusts, which became morphologically more pronounced proceeding from the Atlantic lowlands to the southernmost Andean Cordillera, dominate the central sector of the Tierra del Fuego Island. This belt involves both the Mesozoic rocks of the Rocas Verdes marginal basins, and the Cretaceous through Tertiary sedimentary sequences of the Magallanes foreland basin. The Digital Elevation Model derived from the Synthetic Aperture Radar data shows the presence of a noticeable W-E-trending lineament, associated in its westernmost part to a narrow depression, which traverses the central-eastern Tierra del Fuego from the eastern shore of the Lago Fagnano to the Atlantic coast. It is constituted by several segments in an en-enchelon arrangement, and represents a significant part of the Magallanes-Fagnano fault system, one of the major portions of the present-day South America-Scotia plate boundary. Data strongly suggest that the identified tectonic lineament (and subsidiary structures) is transtensional in nature, as documented by seismic reflection profiles acquired off the Atlantic coast, where noticeable fault-controlled basins are present, and spatially superposed on the pre-existing fold and thrust belt system.