Lithospheric flexure and bending of the Central Andes

Watts, A. B.; Lamb, Simon; Fairhead, J. D.; Dewey, John

doi:10.1016/0012-821x(95)00095-t

Cited by 119 publications

(112 citation statements)

References 20 publications

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“…The presence at this longitude of the Brazilian Shield has also been proposed by other authors (e.g. Wigger et al, 1994;Watts et al, 1995;Beck and Zandt, 2002;McQuarrie et al, 2005).…”

Section: -The Easternsupporting

confidence: 82%

“…This situation has also been suggested by other authors (e.g. Watts et al, 1995;Allmendiger et al, 1997;. The identification of fault systems or thrusts that penetrate the entire crust as detected by deep-seismic reflection data at 27°S (Cristallini et al, 2004) is still needed to image the distribution of crustal shortening on the eastern part of the Andes at the latitude of the Altiplano.…”

Section: The Central Andes At 21°s and The Altiplano Plateaumentioning

confidence: 60%

“…A flexurally strong lithosphere, as suggested by Watts et al (1995), should play a key role in the configuration of the Brazilian Shield anomaly and explain foreland deformation in the thin-skinned fold-and-thrust belt. The…”

Section: -The Easternmentioning

confidence: 90%

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More constraints to determine the seismic structure beneath the Central Andes at 21°S using teleseismic tomography analysis

Heit¹,

Koulakov²,

Asch³

et al. 2008

Journal of South American Earth Sciences

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A set of seismological stations was deployed in the Central Andes region along a ~600 km long profile at 21°S between Chile and Bolivia and operated for a period of almost two years, from March 2002 to January 2004. Here we present the results of the tomographic inversion for P-wave velocity anomalies, based on teleseismic data recorded at the stations. The reliability of the results has been checked by a series of synthetic tests. The tomographic images show high-velocities on the west of the profile that are indicative of cold material from the fore-arc. A low-velocity anomaly is detected at the border between the fore-and the volcanic arc where the Quebrada Blanca seismic anomaly was previously described. This anomaly might be related to the presence of fluids that originate at the cluster of earthquakes at a depth of ~100 km in the subducted plate. A strong low-velocity anomaly is detected beneath the entire Altiplano plateau and part of the Eastern Cordillera, in agreement with previous receiver function results. The Brazilian Shield is thought to be responsible for the strong high-velocity anomaly underneath the Interandean and Subandean regions.

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“…The presence at this longitude of the Brazilian Shield has also been proposed by other authors (e.g. Wigger et al, 1994;Watts et al, 1995;Beck and Zandt, 2002;McQuarrie et al, 2005).…”

Section: -The Easternsupporting

confidence: 82%

Section: The Central Andes At 21°s and The Altiplano Plateaumentioning

confidence: 60%

See 1 more Smart Citation

More constraints to determine the seismic structure beneath the Central Andes at 21°S using teleseismic tomography analysis

Heit¹,

Koulakov²,

Asch³

et al. 2008

Journal of South American Earth Sciences

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“…Signiicant variations in the crustal thickness of Andes have been previously pointed out by geological studies [53]. Moreover, the lithospheric lexure of the central Andes and the corresponding bending of stratigraphic sequences have been investigated in detail [54].…”

Section: Introductionmentioning

confidence: 86%

Introductory Chapter: An Introduction to the Seismic and Sequence Stratigraphy and to the Integrated Stratigraphy: Concepts and Meanings

Aiello¹

2017

Seismic and Sequence Stratigraphy and Integrated Stratigraphy - New Insights and Contributions

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“…North and south of the central Altiplano where the average topography is higher, warm asthenospheric material would fill the gap between the crust and the subducting plate. Watts et al (1995) using gravity data to calculate along strike changes in flexural rigidity, and Whitman et al (1996) interpreting their seismic attenuation models, argue that the Altiplano bend region is composed of mechanically strong lithosphere, whereas the Puna region is composed of a thin and hot lithosphere. The coincidence of thin lithosphere with the area affected by Cretaceous rifting (25°S, Santa Barbara system) suggests that thin lithosphere may have been inherited from Mesozoic extension (Kley, 1996;Sempéré et al, 2002), which would have been less active in the Altiplano area.…”

Section: Geophysical Measurements and Heterogeneity Of The Mantlementioning

confidence: 99%

Possible orogeny-parallel lower crustal flow and thickening in the Central Andes

2005

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The relatively low elevation and thick crust in the Altiplano, in comparison to the higher elevation, but thinner crust in the Puna plateau, together with geophysical data, suggest that isostatic equillibrium is achieved by cooler and denser lithospheric mantle in the Altiplano. Excess density in the Altiplano mantle could create differential horizontal stress in the order of 25 MPa between both lithospheric columns. Numerical models accounting for pressure and temperature-dependent rheology show that such stress can induce horizontal ductile flow in the lower crust, from the Puna towards the Altiplano. With a minimum viscosity of 10 19 Pa.s, this flow reaches 1 cm/yr, displacing more than 50 km of material within 5 Ma. If the lower crust viscosity is smaller, the amount of orogeny-parallel lower crustal flow can be even greater. Such a mechanism of channel flow may explain that different amounts of crustal material have been accomodated by shortening in the Altiplano and in the Puna. Because of the strength of the -brittle -upper crust, this channel flow does not necessitate large amounts of suface deformation (except vertical uplift), making it difficult to detect from the geology.

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Lithospheric flexure and bending of the Central Andes

Cited by 119 publications

References 20 publications

More constraints to determine the seismic structure beneath the Central Andes at 21°S using teleseismic tomography analysis

More constraints to determine the seismic structure beneath the Central Andes at 21°S using teleseismic tomography analysis

Introductory Chapter: An Introduction to the Seismic and Sequence Stratigraphy and to the Integrated Stratigraphy: Concepts and Meanings

Possible orogeny-parallel lower crustal flow and thickening in the Central Andes

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