Skip to Main content Skip to Navigation

Limited impact of Quaternary glaciations on denudation rates in Central Asia

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 10Be 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 10Be 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, ∼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 (×5) 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.
Complete list of metadatas

https://hal.archives-ouvertes.fr/hal-01685766
Contributor : Gm Aigle <>
Submitted on : Tuesday, January 16, 2018 - 4:52:09 PM
Last modification on : Wednesday, December 4, 2019 - 4:30:12 PM

Identifiers

Citation

Nicolas Puchol, Julien Charreau, Pierre-Henri Blard, Jerome Lave, Stephane Dominguez, et al.. Limited impact of Quaternary glaciations on denudation rates in Central Asia. Geological Society of America Bulletin, Geological Society of America, 2017, 129 (3-4), pp.479-499. ⟨10.1130/B31475.1⟩. ⟨hal-01685766⟩

Share

Metrics

Record views

215