Environmental controls on <sup>10</sup>Be‐based catchment‐averaged denudation rates along the western margin of the Peruvian Andes

Reber, Regina; Delunel, Romain; Schlunegger, Fritz; Litty, Camille; Madella, Andrea; Akçar, Naki; Christl, Marcus

doi:10.1111/ter.12274

Cited by 19 publications

(38 citation statements)

References 27 publications

(59 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Generally, higher rates are reported in southern Peru than in northern Chile but correlations with precipitation or hillslope angles are inconsistent (Abbühl et al, 2011; Kober et al, 2009; Reber et al, 2017; Starke et al, 2017) and extreme climatic events (e.g., El Niño) may be important (Abbühl et al, 2010). While local erosion rates on hyperarid surfaces in the Central Depression of northern Chile may be negligible on millennial and even million‐year timescales (Dunai et al, 2005; Kober et al, 2007), intermittent hyperaridity (e.g., Jordan et al, 2014) and the wide range of local and catchment‐averaged erosion rates in the fore arc indicated by these methods is consistent with long‐term semiaridity to aridity suggested by mean exhumation rates on low‐temperature thermochronometry timescales.…”

Section: Discussionmentioning

confidence: 99%

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

2018

View full text Add to dashboard Cite

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.

show abstract

Section: Discussionmentioning

confidence: 99%

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

2018

View full text Add to dashboard Cite

show abstract

“…(e) Catchment averaged denudation rates have been corrected for quartz contents (Reber et al, 2017). (f) Mean annual precipitation rates (Reber et al, 2017). (g) Mean annual water discharge (Reber et al, 2017).…”

Section: Morphological Settingmentioning

confidence: 99%

“…The three lines represent maximum, mean and minimum elevations within the selected swath. (e) Catchment averaged denudation rates have been corrected for quartz contents (Reber et al, 2017). (f) Mean annual precipitation rates (Reber et al, 2017).…”

Section: Morphological Settingmentioning

confidence: 99%

“…Little to nearly zero clastic material is derived from the headwa- Figure 2. Topography of the subducting Nazca plate, where slab depth data have been extracted from http://earthquake.usgs.gov/data/slab/ modified from Reber et al (2017). This N-S projection also illustrates (a) tectonic lineaments such as submarine ridges, MFZ: Mendaña fracture zone, NFZ: Nazca fracture zone, (b) Holocene volcanoes, (c) earthquake data taken from http://earthquake.usgs.gov/earthquakes/search/ , number of earthquakes with M > 4 within a 30 km radius window and (d) coastal elevation.…”

Section: Morphological Settingmentioning

confidence: 99%

“…These inferences have been made based on concentrations of in situ cosmogenic 10 Be measured in river-borne quartz (Abbühl et al, 2011;Carretier et al, 2015;Reber et al, 2017) and on morphometric analyses of the western Andean landscape . Accordingly, erosion along the western Peruvian Andes has been related to either the occurrence of earthquakes and thus tectonic processes (McPhillips et al, 2014) or rainfall rates (Abbühl et al, 2011;Carretier et al, 2015) and to the stream's mean annual run-off and thus climatic processes (Reber et al, 2017). Therefore, we hypothesize that hillslope erosion paired with the stream runoff is likely to have a measurable impact on the grain size pattern in the Peruvian streams.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Possible threshold controls on sediment grain properties of Peruvian coastal river basins

2017

Self Cite

View full text Add to dashboard Cite

Abstract. To determine possible controls on sediment grain properties, 21 coastal rivers located along the entire western Peruvian margin were analysed. This represents one of the largest grain size dataset that has been collected over a large area. Modern gravel beds were sampled along a north-south transect on the western side of the Peruvian Andes where the rivers cross the tip of the mountain range, and at each site the long a axis and the intermediate b axis of about 500 pebbles were measured. Morphometric properties of each drainage basin, sediment and water discharge, together with flow shear stresses, were determined and compared against measured grain properties. Pebble size data show that the values for the D 50 are nearly constant and range between 2 and 3 cm, while the values of the D 96 range between 6 and 12 cm. The ratios between the intermediate and the long axis range from 0.67 to 0.74. Linear correlations between all grain size percentiles and water shear stresses, mean basin denudation rates, mean basin slopes and basin sizes are small to non-existent. However, exceptionally large D 50 values of 4-6 cm were measured for basins situated between 11-12 and 16-17 • S latitude where hillslope gradients are steeper than on average or where mean annual stream flows exceed the average values of the western Peruvian streams by a factor of 2. We suggest that the generally uniform grain size pattern has been perturbed where either mean basin slopes or water fluxes exceed threshold conditions.

show abstract

Possible climatic controls on the accumulation of Peru's most prominent alluvial fan: The Lima Conglomerate

Litty

Schlunegger

Akçar

et al. 2018

Earth Surf Processes Landf

Self Cite

View full text Add to dashboard Cite

Sediment accumulation can occur in response to a change in either tectonic or climatic driving forces. Here, we explore these controls on the deposition of the Lima Conglomerate, Peru. We use a combination of quantitative methods to explore the age of sediment accumulation, the provenance of the material and the paleo‐erosion rates recorded by these deposits. Isochron burial dating with cosmogenic 10Be and 26Al yield an age of c. 500 ka for the base (490 ± 70 ka) and the uppermost sample situated c. 30 m higher upsection (490 ± 80 ka). Results of paleo‐erosion rate estimates with concentrations of in situ 10Be show a c. 60% increase from 105 ± 10 mm ka‐1 for the base to 169 ± 14 mm ka‐1 for the uppermost sample. Finally, provenance tracing with in situ U/Pb ages on detrital zircon implies that the material has been derived from the entire drainage basin. The combination of results suggests that sediment accumulation occurred in response to an erosional pulse, which affected the entire basin within a short time interval. Because 10Be data represents a large spatial record of erosion, we exclude the possibility where a breakout of a lake or a focused release of material in response to earthquakes, were responsible for the large material flux. Instead, the erosional pulse was likely to have occurred at the scale of the entire basin, supporting the idea of a larger‐scale, most likely climate driven control. In this context, the accumulation age of c. 500 ka falls into an orbital cycle fostering the emerging picture in the literature that sediment routing in the Andes have most likely been driven by climate and cyclic changes. We suggest that the Andean mountain range offers an ideal laboratory to explore the erosional history in relation to climate patterns, at least in Peru. © 2018 John Wiley & Sons, Ltd.

show abstract

Environmental controls on ¹⁰Be‐based catchment‐averaged denudation rates along the western margin of the Peruvian Andes

Cited by 19 publications

References 27 publications

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

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

Possible threshold controls on sediment grain properties of Peruvian coastal river basins

Possible climatic controls on the accumulation of Peru's most prominent alluvial fan: The Lima Conglomerate

Contact Info

Product

Resources

About

Environmental controls on 10Be‐based catchment‐averaged denudation rates along the western margin of the Peruvian Andes

Cited by 19 publications

References 27 publications

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

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

Possible threshold controls on sediment grain properties of Peruvian coastal river basins

Possible climatic controls on the accumulation of Peru's most prominent alluvial fan: The Lima Conglomerate

Contact Info

Product

Resources

About

Environmental controls on ¹⁰Be‐based catchment‐averaged denudation rates along the western margin of the Peruvian Andes