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Limited impact of Quaternary glaciations on denudation rates in Central Asia

Nicolas Puchol, Julien Charreau, Pierre-Henri Blard, Jerome Lave, Stephane Dominguez, Raphael Pik and Dimitri Saint-Carlier
Limited impact of Quaternary glaciations on denudation rates in Central Asia
Geological Society of America Bulletin (October 2016) 129 (3-4): 479-499

Abstract

Because of its essential role in coupling climate and tectonics, denudation is a key parameter when constraining the history of Earth's surface. This is particularly true at the Pliocene-Pleistocene transition, and the potential impact of the onset of Quaternary glaciations remains strongly debated. In the present study, we measured in situ cosmogenic (super 10) Be within continuous late Cenozoic sedimentary sections that had already been dated using magnetostratigraphy. The new data were obtained from four sedimentary basins in the northern and southern Tianshan range (Central Asia). We first thoroughly discuss how in situ cosmogenic (super 10) Be concentrations can be corrected for radioactive decay and for the contribution of postdepositional cosmogenic accumulation to derive the paleo-denudation rates. Our analysis shows that, in the four sedimentary records, the potential bias remains low enough to consider the derived denudation rates reliable. The four records, although likely influenced by local particularities due to lithological heterogeneity and local tectonics, display similar trends of continuously increasing denudation between ca. 9 Ma and the present. These rates have remained relatively high but steady since 4 Ma, approximately 1.5 m.y. before the onset of the Quaternary glacial cycles. Though the rejuvenation of the Tianshan range since 11 Ma may explain most of the progressive increase (X5) in denudation, our data suggest that the Quaternary glaciations had only a limited impact on denudation in the Tianshan. Our data, however, indicate an increase in the spatial and high-frequency variability (<1 m.y.) of the denudation rates between 3 and 1 Ma. This may correspond to a transient readjustment of the landscape in response to the onset of Quaternary glacial cycles.


ISSN: 0016-7606
EISSN: 1943-2674
Coden: BUGMAF
Serial Title: Geological Society of America Bulletin
Serial Volume: 129
Serial Issue: 3-4
Title: Limited impact of Quaternary glaciations on denudation rates in Central Asia
Affiliation: Universite de Lorraine, Centre de Recherches Petrographiques et Geochimiques, Vandoeuvre-les-Nancy, France
Affiliation: Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Team
Pages: 479-499
Published: 20161021
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 92
Accession Number: 2016-094602
Categories: Quaternary geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 3 tables, sketch maps
N43°00'00" - N45°00'00", E83°00'00" - E86°00'00"
Secondary Affiliation: Universite de Montpellier, FRA, FranceAix-Marseille Universite, FRA, France
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201646
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