Details
| Original language | English |
|---|---|
| Pages (from-to) | 431-449 |
| Number of pages | 19 |
| Journal | Quaternary Research (United States) |
| Volume | 91 |
| Issue number | 1 |
| Early online date | 18 Dec 2018 |
| Publication status | Published - 1 Jan 2019 |
Abstract
Alluvial fans record climate-driven erosion and sediment-transport processes and allow reconstructing past environmental conditions. Here we investigate the sedimentation history of two alluvial fans located in formerly glaciated valleys of the Cordillera Oriental, Peru. 10Be exposure ages from the fan surfaces and radiocarbon ages from the fan interiors constrain the final stages of fan formation. The 10Be and 14C ages cluster mainly between 13.3-9.3 ka and 11,500-9700 cal yr BP, respectively. Our age data set indicates that - after deglaciation - large amounts of fan sediment were deposited until ∼10 ka, when sedimentation rates declined rather abruptly. This pattern is supported by 10Be erosion rates for the fan catchments, because under the assumption of constant erosion the time needed to Erode the material stored in the fans significantly exceeds their age. Correlating our ages with regional climate records indicates that precipitation exerts the primary control on fan sedimentation. Two periods with elevated lake levels and increased precipitation between 18 and 14.5 ka and from 13 to 11.5 ka resulted in rapid deposition of large fan lobes. Subsequently, lower precipitation rates decreased erosion in the catchments and sediment delivery to the fans, which have remained largely inactive since ∼9.5 ka.
Keywords
- Be exposure dating, C dating, Alluvial fan, Andes, Climate history, Peru, Sedimentation rate
ASJC Scopus subject areas
- Arts and Humanities(all)
- Arts and Humanities (miscellaneous)
- Earth and Planetary Sciences(all)
- Earth-Surface Processes
- Earth and Planetary Sciences(all)
Sustainable Development Goals
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In: Quaternary Research (United States), Vol. 91, No. 1, 01.01.2019, p. 431-449.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Postglacial alluvial fan dynamics in the Cordillera Oriental, Peru, and palaeoclimatic implications
AU - Ratnayaka, Kevin
AU - Hetzel, Ralf
AU - Hornung, Jens
AU - Hampel, Andrea
AU - Hinderer, Matthias
AU - Frechen, Manfred
N1 - Copyright © University of Washington. Published by Cambridge University Press, 2018.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Alluvial fans record climate-driven erosion and sediment-transport processes and allow reconstructing past environmental conditions. Here we investigate the sedimentation history of two alluvial fans located in formerly glaciated valleys of the Cordillera Oriental, Peru. 10Be exposure ages from the fan surfaces and radiocarbon ages from the fan interiors constrain the final stages of fan formation. The 10Be and 14C ages cluster mainly between 13.3-9.3 ka and 11,500-9700 cal yr BP, respectively. Our age data set indicates that - after deglaciation - large amounts of fan sediment were deposited until ∼10 ka, when sedimentation rates declined rather abruptly. This pattern is supported by 10Be erosion rates for the fan catchments, because under the assumption of constant erosion the time needed to Erode the material stored in the fans significantly exceeds their age. Correlating our ages with regional climate records indicates that precipitation exerts the primary control on fan sedimentation. Two periods with elevated lake levels and increased precipitation between 18 and 14.5 ka and from 13 to 11.5 ka resulted in rapid deposition of large fan lobes. Subsequently, lower precipitation rates decreased erosion in the catchments and sediment delivery to the fans, which have remained largely inactive since ∼9.5 ka.
AB - Alluvial fans record climate-driven erosion and sediment-transport processes and allow reconstructing past environmental conditions. Here we investigate the sedimentation history of two alluvial fans located in formerly glaciated valleys of the Cordillera Oriental, Peru. 10Be exposure ages from the fan surfaces and radiocarbon ages from the fan interiors constrain the final stages of fan formation. The 10Be and 14C ages cluster mainly between 13.3-9.3 ka and 11,500-9700 cal yr BP, respectively. Our age data set indicates that - after deglaciation - large amounts of fan sediment were deposited until ∼10 ka, when sedimentation rates declined rather abruptly. This pattern is supported by 10Be erosion rates for the fan catchments, because under the assumption of constant erosion the time needed to Erode the material stored in the fans significantly exceeds their age. Correlating our ages with regional climate records indicates that precipitation exerts the primary control on fan sedimentation. Two periods with elevated lake levels and increased precipitation between 18 and 14.5 ka and from 13 to 11.5 ka resulted in rapid deposition of large fan lobes. Subsequently, lower precipitation rates decreased erosion in the catchments and sediment delivery to the fans, which have remained largely inactive since ∼9.5 ka.
KW - Be exposure dating
KW - C dating
KW - Alluvial fan
KW - Andes
KW - Climate history
KW - Peru
KW - Sedimentation rate
UR - http://www.scopus.com/inward/record.url?scp=85064984002&partnerID=8YFLogxK
U2 - 10.1017/qua.2018.106
DO - 10.1017/qua.2018.106
M3 - Article
AN - SCOPUS:85064984002
VL - 91
SP - 431
EP - 449
JO - Quaternary Research (United States)
JF - Quaternary Research (United States)
SN - 0033-5894
IS - 1
ER -