Tectonic inversion in the Santa Barbara System of the central Andean foreland thrust belt, northwestern Argentina

Abstract

[1] The Santa Barbara System (SBS) of northern Argentina is a 400 km long segment of the Subandean foreland thrust belt. It is characterized by predominantly west verging, relatively high-angle thrust faults. Many of these faults are reactivated normal faults from one branch of a complex Cretaceous to Paleogene rift system. Heteroaxial folding in parts of the SBS is probably due to a slight component of range-parallel dextral strike-slip motion acting on preexisting faults striking north and NE during inversion. Regional balanced cross sections along two transects across the northern SBS indicate that the major faults flatten into a detachment in the basement at about 10 km depth. Neogene E-W contraction in the SBS is of the order of 21-26 km. Rift extension is not very well constrained but was probably less than 10 km. The structural style of the SBS differs from the thin-skinned Subandean thrust belt to the north and from the large-wavelength Sierras Pampeanas basement uplifts to the south. The changes between the different styles are sharp and coincide with the northern and southern boundaries of the rift in the foreland, suggesting that crustal or lithospheric heterogeneities exert an overriding control on foreland structural style.

Basin fragmentation controlled by tectonic inversion and basement uplift in Sierras Pampeanas and Santa Bárbara System, northwest Argentina

“…The tectonic inversion of former extensional faults played a key role in the configuration of the Santa Bárbara System, at the NE of the study area (Grier et al 1991;Coutand et al 2001;Kley et al 2005;Carrera et al 2006;Hongn et al 2007). The Eastern Cordillera involves the inversion of Cretaceous syn-rift faults, but also basement faults that were not active during the rifting stage (Bianucci et al 1981;Grier et al 1991;Cristallini et al 1997;Kley & Monaldi 2002).…”

The role of inherited extensional fault segmentation and linkage in contractional orogenesis: a reconstruction of Lower Cretaceous inverted rift basins in the Eastern Cordillera of Colombia

“…For example, mild to moderate inversion in intraplate basins has been observed in numerous North Atlantic basins (Cartwright, 1989;Chapman, 1989;Hayward & Graham, 1989;Roberts et al, 1993;Sinclair, 1995;Thomas & Coward, 1995) or in the North German Basin (Kossow et al, 2000;Kossow & Krawczyk, 2002;Gemmer et al, 2003). In addition, strongly shortened half grabens have been documented in the Alps (Gillcrist et al, 1987), with prominent examples found in the Central Andes (Kley & Monaldi, 2002) and Atlas mountains (Beauchamp et al, 1999;Teixell et al, 2003). Huyghe & Mugnier (1995) suggested that the nature of inversion in mildly inverted intraplate basins is di¡erent from inversion in orogenic belts where extensional structures are typically fully reversed, creating topography and exposure of former basin strata (e.g.…”

The Southern Central Andes vertical axis tectonic rotations: relations with the deformation pattern

“…This low resolution image of deformation was complemented by a detailed analysis of shortening across the plateau at 21°S±1° by Oncken et al (2006). They used the available data on horizontal shortening (e.g., Kley and Monaldi, 2002;Echavarría et al, 2003;Elger et al, 2005) and recently published ages from synkinematic growth deposits and unconformities (e.g., Horton, 2005;Ege, 2004). They collected such data for all individual structures building each morphotectonic unit of the Southern Central Andes.…”