Kinematic model for basement configuration at Atuel river valley, Mendoza province, Argentina.

FORTUNATTI, NATALIA; DIMIERI, LUIS

BOLLETTINO DI GEOFISICA TEORICA ED APPLICATA

ISTITUTO NAZIONALE DI OCEANOGRAFIA E DI GEOFISICA

Año: 2013 vol. 54 p. 51 - 54

0006-6729

At the Atuel river Valley area, Malargüe Fold and Thrust belt, southern Central Andes, Mendoza province, Argentina (34° 40? ? 35° S and 69° - 70°W) (Fig. 1a), mountain range morphology is related to the evolution of South America plate active margin. During the at Late Mesozoic extensional tectonic configuration involved igneous activity and island arc and backarc basins creation, while Tertiary Andean orogeny defined a mountain belt, whose structural style was controlled by the subduction angle of the Nazca plate (Gansser, 1973; Ramos, 1988, 1999). Nevertheless, kinematic evolution of the area is still a matter of controversy. According to Manceda and Figueroa (1995), Giambiagi et al. (2005 a, b), Giambiagi et al. (2008 a, b), Bechís et al. (2009, 2010) among others, tectonic inversion of Triassic normal faulting is relevant in the process of mountain front construction. Dimieri (1992, 1997), Dimieri and Nullo (1993), Dimieri et al. 2005, Dimieri and Turienzo (2012), Fortunatti (2009, 2011a, b), Kozlowski et al. 1993, Turienzo and Dimieri (2005 a, b, c; 2006), Turienzo et al. (2004, 2010) and Turienzo (2010) concluded that Andean compressional forces necessarily involved low-angle faulting in order to transfer shortening to sedimentary cover at the Malargüe Fold and Thrust belt. This contribution analyzes a new structural kinematic model for the studied region of the southern Central Andes, supported on detailed field work, well and seismic available data. Three West-East structural sections sub-perpendicular to Andean tectonic structures were interpreted and balanced. Complex structures resolution lead us to review previous kinematic models, in order to fully understand compressional tectonics in the mountain front of the Principal Cordillera (Fortunatti, 2009, 2011 a, b). Our research shows that opposite-vergent thrust systems and triangle zones represent a common feature that necessarily has to be related to subsurface basement geometry.