End member models for Andean Plateau uplift

Barnes, J. B.; Ehlers, Todd A.

doi:10.1016/j.earscirev.2009.08.003

Cited by 171 publications

(186 citation statements)

References 249 publications

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“…In the wake of these extremes and at the margin of an actively subducting plate, one could expect to see ongoing mountain‐producing deformation at the leading edge of the range. Instead, indicators of exhumation and erosion such as mineral cooling ages have documented processes an order of magnitude older in parts of the Andes than what we see in other convergent orogens (e.g., Barnes & Ehlers, 2009; Masek et al, 1994). Understanding the mechanisms behind such long‐lived slow mountain building, and decoupling the relative contributions made by tectonic and climatic processes, has long been a challenge in this field of research.…”

Section: Introductioncontrasting

confidence: 63%

“…Rates prior to ZHe closure are not interpreted here, because they are more likely to influence the timing of pluton emplacement and postcrystallization cooling. In the CC this uniformity occurs between ~100 and 60 Ma, during the Cretaceous, and in the PC, between ~40 to 50 Ma, coeval with estimates of early Eocene Andes mountain building (Barnes & Ehlers, 2009; McQuarrie et al, 2005; Sempere et al, 1990). A possible decrease in exhumation in the PC could be indicated by the slightly lower rates in the AHe‐to‐present time steps as compared to the ZHe‐to‐AHe time steps.…”

Section: Discussionmentioning

confidence: 64%

“…Notably, three distinctly oriented sections of the range (Figure 1) may be the result of differential shortening recording periods of Andean deformation and uplift (Allmendinger et al, 1997; Isacks, 1988; Roperch et al, 2006), though this uniquely bent geometry may itself lead to focused deformation in the upper plate, particularly at plate corners (e.g., Bendick & Ehlers, 2014; Jordan et al, 1983). Other tectonic controls have been invoked to explain variation in Andean morphology (i.e., angle of convergence, convergence velocity, age of oceanic crust, and trench orientation), though no clear consensus exists on their relative importance (e.g., Barnes & Ehlers, 2009; Maloney et al, 2013; Oncken et al, 2006). Broad regional uplift has been tied to removal of lithospeheric material through either gradual subduction erosion or rapid lower lithosphere removal of a high‐density crustal root (e.g., delamination; Garzione et al, 2008, 2017).…”

Section: Field Settingmentioning

confidence: 99%

“…Although subduction along the Andean margin started as early as the Jurassic (~200 Ma) (James, 1971; Rutland, 1971), most of the uplift that has produced the Altiplano‐Puna Plateau (~3,800‐m mean elevation) has occurred only since the Paleocene and Eocene (~60–40 Ma; Barnes & Ehlers, 2009; McQuarrie et al, 2005; Sempere et al, 1990). The timing and mechanism of this uplift has been largely debated (e.g., Barnes & Ehlers, 2009; Ehlers & Poulsen, 2009; Garzione et al, 2008, 2017), and the timing and rate of exhumation along the margin, intrinsically tied to uplift, can thus be difficult to decouple from its tectonic controls.…”

Section: Field Settingmentioning

confidence: 99%

“…The timing and mechanism of this uplift has been largely debated (e.g., Barnes & Ehlers, 2009; Ehlers & Poulsen, 2009; Garzione et al, 2008, 2017), and the timing and rate of exhumation along the margin, intrinsically tied to uplift, can thus be difficult to decouple from its tectonic controls.…”

Section: Field Settingmentioning

confidence: 99%

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Slow Long‐Term Exhumation of the West Central Andean Plate Boundary, Chile

2018

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We present a regional analysis of new low‐temperature thermochronometer ages from the Central Andean fore arc to provide insights into the exhumation history of the western Andean margin. To derive exhumation rates over 10 million‐year timescales, 38 new apatite and zircon (U‐Th)/He ages were analyzed along six ~500‐km long near‐equal‐elevation, coast parallel, transects in the Coastal Cordillera (CC) and higher‐elevation Precordillera (PC) of the northern Chilean Andes between latitudes 18.5°S and 22.5°S. These transects were augmented with age‐elevation profiles where possible. Results are synthesized with previously published thermochronometric data, corroborating a previously observed trenchward increase in cooling ages in Peru and northern Chile. One‐dimensional thermal‐kinematic modeling of all available multichronometer equal‐elevation samples reveals mean exhumation rates of <0.2 km/Myr since ~50 Ma in the PC and ~100 Ma in the CC. Regression of pseudovertical age‐elevation transects in the CC yields comparable rates of ~0.05 to ~0.12 km/Myr between ~40 and 80 Ma. Differences between the long‐term mean 1‐D rates and shorter‐term age‐elevation‐derived rates indicate low variability in the exhumation history. Modeling results suggest similar background exhumation rates in the CC and PC; younger ages in the PC are largely a function of increased heat flow and consequently an elevated geothermal gradient near the arc. Slow exhumation rates are suggestive of semiarid conditions across the region since at least the Eocene and deformation and development of the Andean fore arc around this time.

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Section: Introductioncontrasting

confidence: 63%

Section: Discussionmentioning

confidence: 64%

Section: Field Settingmentioning

confidence: 99%

Section: Field Settingmentioning

confidence: 99%

Section: Field Settingmentioning

confidence: 99%

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Slow Long‐Term Exhumation of the West Central Andean Plate Boundary, Chile

2018

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Vegetation-precipitation controls on Central Andean topography

Jeffery

Yanites

Poulsen

et al. 2014

J. Geophys. Res. Earth Surf.

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Climatic controls on fluvial landscapes are commonly characterized in terms of mean annual precipitation. However, physical erosion processes are driven by extreme events and are therefore more directly related to the intensity, duration, and frequency of individual rainfall events. Climate also influences erosional processes indirectly by controlling vegetation. In this study, we explore how interdependent climate and vegetation properties affect landscape morphology at the scale of the Andean orogen. The mean intensity, duration, and frequency of precipitation events are derived from the TRMM 3B42v7 product. Relationships between mean hillslope gradients and precipitation event metrics, mean annual precipitation, vegetation, and bedrock lithology in the central Andes are examined by correlation analyses and multiple linear regression. Our results indicate that mean hillslope gradient correlates most strongly with percent vegetation cover (r = 0.56). Where vegetation cover is less than 95%, mean hillslope gradients increase with mean annual precipitation (r = 0.60) and vegetation cover (r = 0.69). Where vegetation cover is dense (>95%), mean hillslope gradients increase with increasing elevation (r = 0.74), decreasing inter-storm duration (r = À0.69), and decreasing precipitation intensity by~0.5°/(mm d À1 ) (r = À0.56). Thus, we conclude that at the orogen scale, climate influences on topography are mediated by vegetation, which itself is dependent on mean annual precipitation (r = 0.77). Observations from the central Andes are consistent with landscape evolution models in which hillslope gradients are a balance between rock uplift, climatic erosional efficiency and erosional resistance of the landscape determined by bedrock lithology and vegetation.

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