SciELO - Scientific Electronic Library Online

 
vol.39 número2El Basamento de la Cordillera Frontal de los Andes en el Cordón del Plata (Mendoza, Argentina): Evolución GeodinámicaRotaciones tectónicas según ejes verticales en los Andes Centrales del Sur: relaciones con el patrón de deformación índice de autoresíndice de materiabúsqueda de artículos
Home Pagelista alfabética de revistas  

Andean geology

versión On-line ISSN 0718-7106

Resumen

MARTINEZ, Fernando; ARRIAGADA, César; MPODOZIS, Constantino  y  PENA, Matías. The Lautaro Basin: A record of inversion tectonics in northern Chile. AndGeo [online]. 2012, vol.39, n.2, pp. 258-278. ISSN 0718-7106.

The Triassic and Jurassic tectonic history of northern Chile has been dominated by extension, although clear evidence about the nature and geometry of the extensional basins and subsequent inversion structures has been adequately illustrated in only a few cases. In this contribution we present a structural study of the Lautaro Basin located at the western edge of the Frontal Cordillera in the Atacama region of northern Chile. The Lautaro Basin is a Jurassic half-graben, filled by at least 2,600 m of marine deposits of the Lautaro Formation and developed on top of, at least 2,000 m of Triassic volcanic successions of the La Ternera Formation, also accumulated during an earlier period of extensional deformation. Detailed field mapping and construction of a regional balanced cross-section, supported by good exposures along the Copiapó River valley, allow reconstruction of the structural style of both the Jurassic and Triassic extensional depocenters. New structural data have shown that the Lautaro Basin has a complex structural framework reflected in two major Mesozoic extensional periods, overprinted by Cenozoic inversion involving thin- and thick-skinned tectonics. Shortening was accommodated by a combination of inversion of pre-existing normal faults, buttresses, development of footwall short-cuts, and both thin and thick-skinned thrusting. New estimates of shortening are up to 13.1 km (30%), while Mesozoic extension is estimated to be 3 km (7%).

Palabras clave : Lautaro Basin; Half-graben; Balanced cross section; Inversion tectonics; Northern Chile.

        · resumen en Español     · texto en Inglés     · pdf en Inglés