Crustal shortening in the Andes: Why do GPS rates differ from geological rates?

Liu, Mian; Yang, Yongqiang; Stein, Seth; Zhu, Yuanqing; Engeln, Joe

doi:10.1029/2000gl008532

Cited by 68 publications

(61 citation statements)

References 22 publications

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“…Because these age estimates play pivotal roles in the calculation of long-term rates of geologic shortening, all existing comparisons to short-term geodetic velocities in the central Andes [e.g., Norabuena et al, 1998;Horton, 1999;Liu et al, 2000;Lamb, 2000;Bevis et al, 2001;Hindle et al, 2002;Khazaradze and Klotz, 2003] must be regarded with extreme caution.…”

Section: Discussionmentioning

confidence: 99%

“…Many investigations of retroarc deformation, crustal thickening, plateau uplift, and foreland basin generation have emphasized the importance of horizontal shortening in driving Andean orogenesis [Isacks, 1988;Roeder, 1988;Sheffels, 1990;Schmitz, 1994;Wigger et al, 1994;Beck et al, 1996;Allmendinger et al, 1997;Lamb and Hoke, 1997]. Recently, GPS studies have provided an opportunity to compare modern displacements to geologic rates of shortening [Norabuena et al, 1998;Horton, 1999;Liu et al, 2000;Lamb, 2000;Bevis et al, 2001;Hindle et al, 2002;Khazaradze and Klotz, 2003]. These comparisons, however, arrive at conflicting conclusions about whether shortening rates have increased, decreased, or remained steady during Cenozoic deformation.…”

Section: Introductionmentioning

confidence: 99%

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Revised deformation history of the central Andes: Inferences from Cenozoic foredeep and intermontane basins of the Eastern Cordillera, Bolivia

2005

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Investigation of Cenozoic deformation, sediment accumulation, and provenance in the Eastern Cordillera of Bolivia at 17–21°S indicates major shortening (60–140 km) and foredeep development followed by limited internal shortening and intermontane basin development. Contrasting histories of shortening, deposition, sediment dispersal, and detrital composition distinguish a formerly extensive Paleogene foredeep exposed along an eastern belt of synclines from a zone of principally Neogene intermontane basins in the central Eastern Cordillera. New 40Ar/39Ar ages of 25–17 Ma for interbedded tuffs reveal latest Oligocene–early Miocene accumulation in intermontane basins at rates <80 m/Myr, several times lower than Andean foredeeps. Although poorly dated, foredeep evolution probably coincided with middle Eocene–Oligocene deformation and denudation in adjoining regions to the west. A mid‐Cenozoic transition from foredeep to intermontane conditions may be attributable to emplacement of a basement‐involved tectonic wedge beneath the Eastern Cordillera. In this interpretation, wedge emplacement drove flexural foredeep subsidence from roughly 40 to 25 Ma, whereas subsequent accumulation occurred in localized internally drained basins in elevated intermontane areas. Regardless of the regional subsurface structural geometry, 40Ar/39Ar ages define a 25–21 Ma onset of intermontane sedimentation that signifies the termination of major upper crustal shortening over large parts of the Eastern Cordillera and possibly the age of initial shortening in the Interandean and Subandean zones to the east. In contrast to several popular models, the revised tectonic history presented here suggests significant pre‐Neogene shortening in the Eastern Cordillera and underscores the large uncertainties in estimates of long‐term shortening rates in the Andes.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Revised deformation history of the central Andes: Inferences from Cenozoic foredeep and intermontane basins of the Eastern Cordillera, Bolivia

2005

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“…A screening of the convergence/shortening ratio could therefore be an indirect way to infer the upper plate viscosity in the different orogens. For example, in the central Andes, the convergence is 73 mm/yr, whereas the shortening is about 40 mm/yr (Liu et al, 2000). Consequently, the convergence/shortening (C/S) ratio is about 1.8, and the subduction rate should be 33 mm/yr.…”

Section: Convergence Versus Shortening and Subduction Ratesmentioning

confidence: 99%

Simple Kinematics of Subduction Zones

Doglioni

Carminati

Cuffaro

2006

International Geology Review

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Two main types of subduction zones can be distinguished: (1) those where the subduction hinge migrates away from the upper plate; and (2) those in which the subduction hinge migrates toward the upper plate. Apart from a few exceptions, this distinction seems to apply particularly for W-directed subduction zones and E-or NE-directed subduction zones, respectively. Moreover, the rate of subduction is larger than the convergence rate along W-directed subduction zones, whereas it is smaller along E-or NE-directed subduction zones. Along W-inclined slabs, the subduction rate is the convergence rate plus the slab retreat rate, which tends to equal the backarc extension rate. Along E-or NE-dipping slabs, the shortening in the upper plate decreases the subduction rate, and no typical backarc basin forms.Relative to the mantle, the W-directed slab hinges are fixed, whereas they move west or southwest along E-or NE-directed subduction zones. The single vergent accretionary prism related to W-directed subduction zones is formed at the expenses of the shallow layers of the lower plate. The orogens generated by E-and NE-dipping subductions are double vergent since the early stages, and upper plate rocks mostly compose them until continental collision takes place, eventually involving the rocks of the lower plate more extensively. The convergence/shortening ratio in this type of orogens is higher than 1 and is inversely proportional to the viscosity of the upper plate. The higher the viscosity, the smaller the shortening and faster the subduction rate. The convergence/shortening ratio along W-directed subduction zones is instead generally lower than 1.W-directed subduction zones provide larger volumes of lithospheric return into the mantle than the opposite E-or NE-directed subduction zones. The latter may contribute to refertilize the shallow upper mantle. These observations suggest that subduction zones are passive features with respect to the far-field velocity of plate motions and the relative "eastward" mantle flow, implicit with a net "westward" rotation of the lithosphere.

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“…However, elastic constitutive equations are usually used to study the short-term deformation of the crust or lithosphere [32,33]. In plate interiors, deep faults always play an important role during the lithospheric deformation [34,35].…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the overall movement of blocks and its peripheral faults should be treated differently in the numerical study. GPS observation is one of the most direct reflection for the short-term tectonic active [33]. It can be used as the boundary conditions in our numerical model.…”

Section: Introductionmentioning

confidence: 99%

The Evolution of Stress and Strain around the Bayan Har Block in the Tibetan Plateau

Sun

Fan

Chunjing

et al. 2015

Journal of Earthquakes

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With the constraint of GPS observation, the tectonic deformation of the Bayan Har block and its periphery faults is investigated based on an elastoplastic plane-stress finite element model. The results show that the elastic model cannot explain the current GPS observation in the Bayan Har block. When East Kunlun fault and Yushu-Xianshuihe fault are under plastic yield state or high strain localization, the calculated velocities fit well with the observation values. It indicates that most of the current shear deformations or strain localizations are absorbed by these two large strike-slip faults. In addition, if the recurrence intervals of large earthquakes are used to limit the relative yield strength of major faults, the order of entering the plastic yield state of the major faults around Bayan Har block is as follows. The first faults to enter the yield state are Yushu-Xianshuihe faults and the middle segment of East Kunlun faults. Then, Margaichaka-RolaKangri faults (Mani segment) and Heishibeihu faults would enter the yield state. The last faults to enter the yield state are the eastern segment of East Kunlun faults and Longmenshan faults, respectively. These results help us to understand the slip properties of faults around the southeastward moving Bayan Har block.

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Crustal shortening in the Andes: Why do GPS rates differ from geological rates?

Cited by 68 publications

References 22 publications

Revised deformation history of the central Andes: Inferences from Cenozoic foredeep and intermontane basins of the Eastern Cordillera, Bolivia

Revised deformation history of the central Andes: Inferences from Cenozoic foredeep and intermontane basins of the Eastern Cordillera, Bolivia

Simple Kinematics of Subduction Zones

The Evolution of Stress and Strain around the Bayan Har Block in the Tibetan Plateau

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