Magmatic activity and strike slip tectonics in the southernmost Andes: Kranck pluton, characterization and preliminary AMS survey

CERREDO, M. E.; REMESAL, M.; TASSONE A.; PERONI J. I,; MENICHETTI, M.; LIPPAI, H,

BOLLETTINO DI GEOFISICA TEORICA ED APPLICATA

ISTITUTO NAZIONALE DI OCEANOGRAFIA E DI GEOFISICA

Lugar: Trieste; Año: 2010 vol. 51 p. 65 - 67

0006-6729

Three major strike-slip structures of dominant WNW-ESE trend characterize the southernmost Andes, from N to S: the Magallanes-Fagnano Fault System (which represents the onland boundary between the South America and Scotia plates), the Carbajal Valley Fault System in central Tierra del Fuego and the Beagle Channel Fault System which separates de Tierra del Fuego Island from the southern archipelago. The Neogene cinematic evolution of the Magallanes-Fagnano Fault System (MFS) is characterized by its transtensive nature with associated pull-apart basins both in onland and onshore areas (Lodolo et al., 2003). These major fault systems are near parallel to the main lineaments of the Late Cretaceous to Tertiary Fuegian fold and thrust belt which suggests that the transtensional structures may have developed along preexisting zones of weakness formed by crustal shortening (Klepeis and Austin, 1997). The Jeujepen and Kranck plutons are located along the strike of MFS (Fig. 1A), the former at the western termination of the Río Turbio fault segment and the latter at the eastern tip of the M. Hope-Catamarca-fault segment (Fig. 1B). The alignment of intrusive bodies along the several transforming structures of the southernmost Andes has already been reported as a causal relationship (i.e. the Palaeocene Yamana Granite Suite in Chilean Tierra del Fuego, Cunningham 1993; the Ushuaia Pluton, Peroni et al., 2009; the Jeu Jepen pluton, Cerredo et al., 2000).