Fold and thrust belt structures and strike‐slip faulting at the SE margin of the Salar de Atacama basin, Chilean Andes

Kuhn, Dirk

doi:10.1029/2001tc901042

Cited by 30 publications

(20 citation statements)

References 45 publications

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“…(b) Age distribution of ignimbrites and andesites along Altiplano flank between 18°and 24°S (data compiled from Mortimer [1973]; Baker [1977]; Baker and Francis [1978]; Lahsen [1982]; Vergara and Thomas [1984]; Rutland et al [1965]; Vergara et al [1986]; Muñoz and Charrier [1996]; Wörner et al [2000]; Muñoz et al [2002]) superimposed on time span of activity of west Altiplano fault system at various latitudes as identified here at 20°-21°S and as interpreted from published data (see below). (c) Map shows occurrence of thrust faults at flank of Altiplano as observed by various authors (1, 2 [Muñoz and Charrier, 1996;García et al, 2002]; 3 [this paper]; 4 [Buddin et al, 1993;Haschke and Günther, 2003]; 5 [Jolley et al, 1990, Mpodozis et al, 2000Jordan et al, 2002, Muñoz et al, 2002; 6 [Kuhn, 2002]; 7 [Sébrier et al, 1988]; 8 [Audin et al, 2002]). …”

Section: Regional Extent and Correlation With Altiplano Developmentmentioning

confidence: 92%

“…They were recently reactivated with transtensional kinematics and some vertical axis block rotations with a clockwise sense [Randall et al, 1996;Kuhn, 2002]. Late Cenozoic plateau evolution, therefore, encountered a forearc largely controlled by magmatic rocks that intruded into, or overlie, deformed sediments and a heterogeneous continental basement.…”

Section: Regional Geomorphology and Geologymentioning

confidence: 99%

“…Here, Jolley et al [1990], Mpodozis et al [2000], Kuhn [2002], Jordan et al [2002], and Muñoz et al [2002] report west and east vergent faults and minor contractional structures at the toe of the flanks of both Cordilleras and in the Salar. Formation of these structures has occurred during an earlier Paleogene contraction succeeded by a stage of late Miocene (circa 10-11 Ma) to recent reactivation, as indicated by ongoing upper crustal seismicity.…”

Section: Regional Extent and Correlation With Altiplano Developmentmentioning

confidence: 99%

“…On a smaller scale, Wörner et al [2000] describe similar large-scale antithetic block rotations at 18°S induced by gravitational collapse of the plateau flank (see, however, controversial discussion by García and Hérail [2001]). In addition, deformation of parts of the forearc has been shown to be dominated by vertical axis block rotations that have been either attributed to oroclinal bending of the Andes [Isacks, 1988;MacFadden et al, 1995;Kuhn, 2002] or to oblique subduction during the Cenozoic [Beck, 1988;Randall et al, 1996].…”

Section: Introductionmentioning

confidence: 99%

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Uplift of the western Altiplano plateau: Evidence from the Precordillera between 20° and 21°S (northern Chile)

2004

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We present a quantitative reconstruction of uplift of the western flank of the Altiplano plateau (central Andes), one of the largest monoclines on the Earth, on the basis of an analysis of tectonic structures, syntectonic deposits, and geophysical data. Uplift occurred on a west vergent, slowly propagating system of high‐angle reverse faults merging into a joint detachment that ramps down to midcrustal levels below the plateau edge. The upper ramps determine local fold geometries while the lower ramp controls large‐scale surface tilting and uplift. At 20°S, this fault system was active between ∼30 Ma and 5–10 Ma, with maximum shortening rates of 0.22 mm/yr between 17 and 10 Ma. It generated some 2600 m of surface uplift with only minor shortening of ∼3000 m. Its activity was largely synchronous to eruption of large‐volume ignimbrites from a midcrustal source. Geophysical data indicate that the fault system localized deformation at the boundary between a cool, strong forearc crust and a presumably fluid‐rich and/or partially molten zone underneath the plateau area. The systematic relation between crustal melting and shortening with uplift at the western plateau margin can be traced along most of the plateau flank, with a stepwise decrease in age of deformation and magmatism toward the south indicating discontinuous addition of plateau segments. Crustal thickening to as much as 70 km from westward underthrusting in the back arc parts of the plateau isostatically compensated the tectonic surface uplift and monocline formation with respect to a stable forearc, which only reacted with minor tilting.

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Section: Regional Extent and Correlation With Altiplano Developmentmentioning

confidence: 92%

Section: Regional Geomorphology and Geologymentioning

confidence: 99%

Section: Regional Extent and Correlation With Altiplano Developmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Uplift of the western Altiplano plateau: Evidence from the Precordillera between 20° and 21°S (northern Chile)

2004

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“…Across two of them, the Neogene sequences have characteristic growth strata (Figure 11). At outcrop, detailed structural mapping has revealed an eastward verging thin‐skinned fold‐and‐thrust belt in strata of Oligocene to Pleistocene age [ Ramírez and Gardeweg , 1982; Kuhn , 2002].…”

Section: Subsurface Structure Of the Basinmentioning

confidence: 99%

Salar de Atacama basin: A record of compressional tectonics in the central Andes since the mid‐Cretaceous

Arriagada¹,

2006

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The Salar de Atacama basin lies in the inner fore arc of northern Chile. Topographically and structurally, it is a first‐order feature of the central Andes. The sedimentary fill of the basin constrains the timing and extent of crustal deformation since the mid‐Cretaceous. We have studied good exposures along the western edge of the basin and have correlated them with seismic reflection sections and data from an exploration well. Throughout most of its history, the basin developed in a foreland setting, during periods of thin‐skinned and thick‐skinned thrusting. Growth strata provide evidence for coeval sedimentation and thrust motions during mid‐Cretaceous, Paleogene, and Neogene times. Pre‐Neogene deformation was significant in the basin and in surounding areas of the early central Andes. Models that attempt to explain the current thickness of the central Andes should consider Late Cretaceous and Paleogene shortening, as well as the more obvious Neogene and Quaternary shortening.

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Temporal variation of the stress field during the construction of the central Andes: Constrains from the volcanic arc region (22-26°S), Western Cordillera, Chile, during the last 20 Ma

Giambiagi

Álvarez²,

Spagnotto

2016

Tectonics

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In order to understand the response of the stress field state to intrinsic processes during the construction of the Andes, such as thickening of the continental crust, lithospheric delamination, and/or thermal weakening, we investigate the stress field evolution of the arc region since the last 20 Myr, in the central Andes (22–26.5°S). The 43 reduced paleostress tensors derived from inversion of 682 fault slip data reveal a complex pattern of stress states during the last episode of orogenic construction and topographic uplift. We identify two geodynamic stages: the first stage corresponds to the construction of the Altiplano/Puna plateau and the second one to its gravitational collapse. Four stress states that have prevailed in the Altiplano/Puna plateau since middle Miocene times characterize the transition from one stage to the other. Along the study latitudes, a spatiotemporal change in stress state is clearly observed, which led to an understanding that a change in the stress field may be related not only to the boundary conditions but also to intrinsic factors associated with the construction of the Andean orogeny. Our results suggest that approximately at 13–10 Ma and approximately 8–5 Ma, in the southern Altiplano and northern Puna, and in the southern Puna, respectively, regional elevation and crustal thicknesses reached threshold values necessary to generate the orogenic collapse.

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Fold and thrust belt structures and strike‐slip faulting at the SE margin of the Salar de Atacama basin, Chilean Andes

Cited by 30 publications

References 45 publications

Uplift of the western Altiplano plateau: Evidence from the Precordillera between 20° and 21°S (northern Chile)

Uplift of the western Altiplano plateau: Evidence from the Precordillera between 20° and 21°S (northern Chile)

Salar de Atacama basin: A record of compressional tectonics in the central Andes since the mid‐Cretaceous

Temporal variation of the stress field during the construction of the central Andes: Constrains from the volcanic arc region (22-26°S), Western Cordillera, Chile, during the last 20 Ma

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