Erosional response of an actively uplifting mountain belt to cyclic rainfall variations
We present an approximate analytical solution to the stream power equation describing the erosion of bedrock in an actively uplifting mountain range subject to periodic variations in precipitation rate. It predicts a time lag between the climate forcing and the erosional response of the system that...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-01-01
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| Series: | Earth Surface Dynamics |
| Online Access: | http://www.earth-surf-dynam.net/3/1/2015/esurf-3-1-2015.pdf |
| _version_ | 1818499621655150592 |
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| author | J. Braun C. Voisin A. T. Gourlan C. Chauvel |
| author_facet | J. Braun C. Voisin A. T. Gourlan C. Chauvel |
| author_sort | J. Braun |
| collection | DOAJ |
| description | We present an approximate analytical solution to the stream power equation
describing the erosion of bedrock in an actively uplifting mountain range
subject to periodic variations in precipitation rate. It predicts a time lag
between the climate forcing and the erosional response of the system that
increases with the forcing period. The predicted variations in the
sedimentary flux coming out of the mountain are also scaled with respect to
the imposed rainfall variations in a direct proportion to the discharge
exponent, <i>m</i>, in the stream power law expression. These findings are
confirmed by 1-D and 2-D numerical solutions. We also show that the response of
a river channel is independent of its length and thus the size of its
catchment area, implying that all actively eroding streams in a mountain belt
will constructively contribute to the integrated signal in the sedimentary
record. We show that rainfall variability at Milankovitch periods should
affect the erosional response of fast uplifting mountain belts such as the
Himalayas, Taiwan or the South Island, New Zealand, and predict 1000 to 10 000-year
offsets between forcing and response. We suggest that this theoretical
prediction could be used to independently constrain the value of the poorly
defined stream power law exponents, and provide an example of how this could
be done, using geochemical proxy signals from an ODP borehole in the Bengal Fan. |
| first_indexed | 2024-12-10T20:31:58Z |
| format | Article |
| id | doaj.art-d645c214332e4806b4d1eea918ce6412 |
| institution | Directory Open Access Journal |
| issn | 2196-6311 2196-632X |
| language | English |
| last_indexed | 2024-12-10T20:31:58Z |
| publishDate | 2015-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Earth Surface Dynamics |
| spelling | doaj.art-d645c214332e4806b4d1eea918ce64122022-12-22T01:34:39ZengCopernicus PublicationsEarth Surface Dynamics2196-63112196-632X2015-01-013111410.5194/esurf-3-1-2015Erosional response of an actively uplifting mountain belt to cyclic rainfall variationsJ. Braun0C. Voisin1A. T. Gourlan2C. Chauvel3ISTerre, Université Grenoble Alpes and CNRS BP 53, 38041 Grenoble CEDEX 9, FranceISTerre, Université Grenoble Alpes and CNRS BP 53, 38041 Grenoble CEDEX 9, FranceISTerre, Université Grenoble Alpes and CNRS BP 53, 38041 Grenoble CEDEX 9, FranceISTerre, Université Grenoble Alpes and CNRS BP 53, 38041 Grenoble CEDEX 9, FranceWe present an approximate analytical solution to the stream power equation describing the erosion of bedrock in an actively uplifting mountain range subject to periodic variations in precipitation rate. It predicts a time lag between the climate forcing and the erosional response of the system that increases with the forcing period. The predicted variations in the sedimentary flux coming out of the mountain are also scaled with respect to the imposed rainfall variations in a direct proportion to the discharge exponent, <i>m</i>, in the stream power law expression. These findings are confirmed by 1-D and 2-D numerical solutions. We also show that the response of a river channel is independent of its length and thus the size of its catchment area, implying that all actively eroding streams in a mountain belt will constructively contribute to the integrated signal in the sedimentary record. We show that rainfall variability at Milankovitch periods should affect the erosional response of fast uplifting mountain belts such as the Himalayas, Taiwan or the South Island, New Zealand, and predict 1000 to 10 000-year offsets between forcing and response. We suggest that this theoretical prediction could be used to independently constrain the value of the poorly defined stream power law exponents, and provide an example of how this could be done, using geochemical proxy signals from an ODP borehole in the Bengal Fan.http://www.earth-surf-dynam.net/3/1/2015/esurf-3-1-2015.pdf |
| spellingShingle | J. Braun C. Voisin A. T. Gourlan C. Chauvel Erosional response of an actively uplifting mountain belt to cyclic rainfall variations Earth Surface Dynamics |
| title | Erosional response of an actively uplifting mountain belt to cyclic rainfall variations |
| title_full | Erosional response of an actively uplifting mountain belt to cyclic rainfall variations |
| title_fullStr | Erosional response of an actively uplifting mountain belt to cyclic rainfall variations |
| title_full_unstemmed | Erosional response of an actively uplifting mountain belt to cyclic rainfall variations |
| title_short | Erosional response of an actively uplifting mountain belt to cyclic rainfall variations |
| title_sort | erosional response of an actively uplifting mountain belt to cyclic rainfall variations |
| url | http://www.earth-surf-dynam.net/3/1/2015/esurf-3-1-2015.pdf |
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