Charreau, J. and Blard, P.-H. and Puchol, N. and Avouac, J.-P. and Lallier-Vergès, E. and Bourlès, D. and Braucher, R. and Gallaud, A. and Finkel, R. and Jolivet, M. and Chen, Y. and Roy, P. (2011) Paleo-erosion rates in Central Asia since 9 Ma: A transient increase at the onset of Quaternary glaciations? Earth and Planetary Science Letters, 304 (1-2). pp. 85-92. ISSN 0012-821X http://resolver.caltech.edu/CaltechAUTHORS:20110503-151958063
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Erosion is a fundamental player of the interactions existing between internal geodynamics and climate, in particular through its influence on the carbon dioxide budget. However, long term (> Ma) erosion rates, estimated indirectly from sediment budget, remain poorly constrained. While some studies suggest that worldwide erosion rates increased at the Plio-Pleistocene climatic transition (~4–2 Ma), the validity of this observation and its significance is a matter of debate due to potential biases of the sedimentary record and to the influence of sea level fall on the global sedimentary flux to marginal basins. In the present study, we estimate erosion rates over the last ~9 Ma using in situ produced cosmogenic ^(10)Be concentrations measured in magnetostratigraphically dated continental sediments. We focus on an intracontinental endorheic watershed draining the northern Tianshan in Central Asia, a key region regarding the ongoing debate. While erosion rates between 0.1 and 1 mm·yr^(−1) are derived from most of our record, they reach values as high as ~2.5 mm·yr^(−1) from 2.5 to 1.7 Ma. Then, after 1.7 Ma, recent andmodern erosion rates fell below 1 mm·yr^(−1). This temporary increase is correlated with the onset of Quaternary ice ages and suggests that global climate had a significant and transient impact on erosion.
|Additional Information:||© 2011 Elsevier B.V. Received 6 December 2010; Received in revised form 18 January 2011; Accepted 18 January 2011; Available online 20 February 2011. Editor: T.M. Harrison. This study was financed by the French INSU/CNRS programs SYSTER and ANR. We thank Peter Molnar and one anonymous reviewer for their very constructive comments that greatly improved the manuscript. Fruitful discussions with Jérôme Lavé and Raphaël Pik were useful for interpreting this record. Expert Jean-Pierre Valet and Yves Gallet are also thanked for their advice about the long term variations in the earth virtual magnetic moment. We are also grateful to Robert Joussemet (STEVAL mineral processing pilot plant, Lem, Nancy) for his help in separating quartz and to the ASTER team for the cosmogenic nuclide concentration measurements (M. Arnold, G. Aumaître, K. Keddadouche, L. Léanni and F. Chauvet). ASTER AMS national facility (CEREGE, Aix en Provence) is supported by the INSU/CNRS, the French Ministry of Research and Higher Education, IRD and CEA. This is CRPG contribution n° 2101.|
|Subject Keywords:||Quaternary glaciation; erosion rates; Tianshan; cosmogenic nuclide; magnetostratigraphy; 10Be|
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|Official Citation:||J. Charreau, P.-H. Blard, N. Puchol, J.-P. Avouac, E. Lallier-Verges, D. Bourles, R. Braucher, A. Gallaud, R. Finkel, M. Jolivet, Y. Chen, P. Roy, Paleo-erosion rates in Central Asia since 9 Ma: A transient increase at the onset of Quaternary glaciations?, Earth and Planetary Science Letters, Volume 304, Issues 1-2, 1 April 2011, Pages 85-92, ISSN 0012-821X, DOI: 10.1016/j.epsl.2011.01.018. (http://www.sciencedirect.com/science/article/B6V61-5275D7F-3/2/a7042fca34b872e35b38b8226e242d61)|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Jason Perez|
|Deposited On:||04 May 2011 14:46|
|Last Modified:||04 May 2011 14:46|
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