Surface uplift and climate change: The geomorphic evolution of the Western Escarpment of the Andes of northern Chile between the Miocene and present

Kober, Florian; Schlunegger, Fritz; Zeilinger, Gerold; Schneider, Heinz

doi:10.1130/2006.2398(05)

Cited by 31 publications

(63 citation statements)

References 34 publications

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“…20 and 7-8 Ma (e.g. Alpers and Brimhall 1988;García and Hérail 2005;Kober et al 2006) and can be correlated several tens of kilometres along strike (Fig. 1b, c).…”

Section: Settingmentioning

confidence: 95%

Sedimentology-based reconstructions of paleoclimate changes in the Central Andes in response to the uplift of the Andes, Arica region between 19 and 21°S latitude, northern Chile

Schlunegger

Kober

Zeilinger

et al. 2010

Int J Earth Sci (Geol Rundsch)

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We focus on the sedimentological record of the Middle Miocene to modern deposits in the Andes of northern Chile between 19 and 21°S. These sediments, deposited at the Western Escarpment of the Central Depression, indicate successively more moisture on the western margin of the Altiplano and the Western Cordillera where the sources are. At the Pacific Coast, 20-Ma-old exposure ages and salic gypsisols reflect an existing and ongoing hyperarid climate. We interpret the increased divergence of climates between the Coast and the Altiplano as consequence of the Andean rise to elevations higher than approximately 2,500 m a.s.l., when the topography of the Altiplano was sufficiently high and areally extensive to attract Atlantic moisture. Accordingly, the inferred general increase in run-off was closely coupled with the uplift of the Andes if the steady rise model applies. In case that the rapid rise model for Andean uplift is correct, the inferred changes in sediment transport would have occurred independently of uplift, requiring an alternative, yet unknown driver.

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“…20 and 7-8 Ma (e.g. Alpers and Brimhall 1988;García and Hérail 2005;Kober et al 2006) and can be correlated several tens of kilometres along strike (Fig. 1b, c).…”

Section: Settingmentioning

confidence: 95%

Sedimentology-based reconstructions of paleoclimate changes in the Central Andes in response to the uplift of the Andes, Arica region between 19 and 21°S latitude, northern Chile

Schlunegger

Kober

Zeilinger

et al. 2010

Int J Earth Sci (Geol Rundsch)

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“…For instance, thanks to its very active tectonics, high precipitation gradient and rate, and the occurrence of large temperate glaciers, the South Island of New Zealand was one of the first cases studied [Adams, 1980;Kirkbride and Matthews, 1997;Koons, 1990;Wellman, 1979]. In the Andes, Montgomery et al [2001] and Strecker et al [2007] addressed the question of whether climatic or geodynamic processes are more important in shaping that landscape, and concluded that climate has a major impact on the landscape and possibly on the tectonic evolution, but many working in the Central Andes have attributed deep incision to surface uplift beginning near or since 10 Ma [Barke and Lamb, 2006;Hoke et al, 2007;Kober et al, 2006;Schildgen et al, 2007;Schlunegger et al, 2006;von Rotz et al, 2005]. Based on Late Pleistocene erosion rates calculated from riverborne cosmogenic 10 Be in SE Tibet, Henck et al [2011] recently postulated that the tectonic setting is more prominent than rainfall or relief to explain erosion rates, but the same method led Moon et al [2011] to the opposite conclusion for the Washington Cascades, where denudation scales with precipitation rate.…”

Section: Introductionmentioning

confidence: 99%

Tectonics, climate, and mountain topography

et al. 2012

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[1] By regressing simple, independent variables that describe climate and tectonic processes against measures of topography and relief of 69 mountain ranges worldwide, we quantify the relative importance of these processes in shaping observed landscapes. Climate variables include latitude (as a surrogate for mean annual temperature and insolation, but most importantly for the likelihood of glaciation) and mean annual precipitation. To quantify tectonics we use shortening rates across each range. As a measure of topography, we use mean and maximum elevations and relief calculated over different length scales. We show that the combination of climate (negative correlation) and tectonics (positive correlation) explain substantial fractions (>25%, but <50%) of mean and maximum elevations of mountain ranges, but that shortening rates account for smaller portions, <25%, of the variance in most measures of topography and relief (i.e., with low correlations and large scatter). Relief is insensitive to mean annual precipitation, but does depend on latitude, especially for relief calculated over small ($1 km) length scales, which we infer to reflect the importance of glacial erosion. Larger-scale (averaged over length scales of $10 km) relief, however, correlates positively with tectonic shortening rate. Moreover, the ratio between small-scale and large-scale relief, as well as the relative relief (the relief normalized by the mean elevation of the region) varies most strongly with latitude (strong positive correlation). Therefore, the location of a mountain range on Earth with its corresponding climatic conditions, not just tectonic forcing, appears to be a key factor in determining its shape and size. In any case, the combination of tectonics and climate, as quantified here, can account for approximately half of the variance in these measures of topography. The failure of present-day shortening rates to account for more than 25% of most measures of relief raises the question: Is active tectonics overrated in attempts to account for present-day relief and exhumation rates of high terrain?

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“…On the western side, the post 10-7 Ma cessation of tectonic shortening 3 was superseded by monoclinal warping 34 . Th is change was associated with a near-termination of surface erosion on the Western Escarpment as indicated by the preservation of post 10 Ma gravel sheets tens of km 2 in area and fl uvial hanging valleys 35 . Deformation as a wedge .…”

Section: Resultsmentioning

confidence: 99%

“…According to circulation models for moisture transport, these elevations were suffi cient to modulate the continentalscale wind and rainfall patterns, and to result in high orographic rainfall gradients in the Eastern Cordillera, enhanced convective rainfall on the Altiplano and the Western Cordillera and blocking of westerly fl ow from the Pacifi c 49,50 . Th e consequence was that the arid / hyperarid climate on the Western Escarpment that already persisted before 14-8 Ma 51 became so dry that erosion nearly terminated, as documented by the preservation of post 10 Ma gravel planes and hanging valleys 35 .…”

Section: Discussionmentioning

confidence: 99%

“…Th e lack of erosion, together with the topographic rise and the steepening of the western ramp, resulted in the triggering of the Lluta collapse, one of largest mass failures on Earth 35 . Th e steepening of the ramp would have shift ed the western margin into a super-critical state and increased the relative friction on steep faults, eff ectively terminating thrusting on the western side and initiating a period of monoclinal warping.…”

Section: Discussionmentioning

confidence: 99%

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