Abstract
Abstract. The Cacheuta sub-basin of the Triassic Cuyo Basin is an example of rift basin inversion contemporaneous to the advance of the Andean thrust front, during the Plio–Quaternary. This basin is one of the most important sedimentary basins in a much larger Triassic NNW-trending depositional system along the southwestern margin of the Pangea supercontinent. The amount and structural style of inversion is provided in this paper by a three-dimensional approach to the relationship between inversion of rift-related structures and spatial variations in late Cenozoic stress fields. The Plio–Quaternary stress field exhibits important N–S variations in the foreland area of the southern Central Andes, between 33 and 34° S, with a southward gradual change from pure compression, with σ1 and σ2 being horizontal, to a strike-slip type stress field, with σ2 being vertical. We present a 3-D approach for studying the tectonic inversion of the sub-basin master fault associated with strike-slip–reverse to strike-slip faulting stress regimes. We suggest that the inversion of Triassic extensional structures, striking NNW to WNW, occurred during the Plio–Pleistocene in those areas with strike-slip–reverse to strike-slip faulting stress regime, while in the reverse faulting stress regime domain they remain fossilized. Our example demonstrates the impact of the stress regime on the reactivation pattern along the faults.
Highlights
In the southern Central Andes of Chile and Argentina, basin inversion of Mesozoic or early Cenozoic extensional basins has always been assigned to compressive stress states during the growth of the orogeny (i.e., Uliana et al, 1995; Godoy et al, 1999; Jordan et al, 2001; Charrier et al, 2002; Giambiagi et al, 2003; Mescua and Giambiagi, 2012; Mescua et al, 2014)
The oil-bearing Triassic Cuyo Basin (Fig. 1a), located in the foreland region of the Andes between 30 and 34◦ S, has been traditionally described as a classical example of Mesozoic rift basins subsequently inverted during the Cretaceous– Quaternary Andean orogeny (Ramos and Kay, 1991; Legarreta et al, 1992; Ávila et al, 2005; Zencich et al, 2008)
The results of this study indicate that the foreland deformation along the southern transitional zone between flatslab and normal subduction segments (33–33◦30 S) shows marked and rapid changes in structural style and a spatial change in the Plio–Quaternary stress field
Summary
In the southern Central Andes of Chile and Argentina, basin inversion of Mesozoic or early Cenozoic extensional basins has always been assigned to compressive stress states during the growth of the orogeny (i.e., Uliana et al, 1995; Godoy et al, 1999; Jordan et al, 2001; Charrier et al, 2002; Giambiagi et al, 2003; Mescua and Giambiagi, 2012; Mescua et al, 2014). The oil-bearing Triassic Cuyo Basin (Fig. 1a), located in the foreland region of the Andes between 30 and 34◦ S, has been traditionally described as a classical example of Mesozoic rift basins subsequently inverted during the Cretaceous– Quaternary Andean orogeny (Ramos and Kay, 1991; Legarreta et al, 1992; Ávila et al, 2005; Zencich et al, 2008) This basin is mainly a subsurface feature (Rolleri and Criado Roque, 1968), buried under more than 3000 m of Cenozoic synorogenic sedimentary cover.
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