EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Contrasting weathering dynamics within continents during the past glacial cycles

Yibo Yang1, Albert Galy2, and Xiaomin Fang1
Yibo Yang et al.
  • 1Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
  • 2Centre de Recherches Pétrographiques et Géochimiques, UMR7358, CNRS, Université de Lorraine, Nancy, France

Chemical weathering of the continental rocks exerts a dominant force on atmospheric CO2 levels and global climate. How continental weathering works during the Quaternary cooling on glacial-interglacial scales is still poorly understood. Here we reconstructed continental weathering history over the past 800 kyr in a High-Mountain Asia catchment impacted by glaciers. The 87Sr/86Sr ratio of lake water, a proxy of catchment weathering, was lower during interglacials while it was higher during glacials and cold stages of interglacials. This higher level in 87Sr/86Sr ratio is assumed to be caused by a glacier-forced release of radiogenic strontium from reactive minerals.

Conversely, 87Sr/86Sr ratio of weathering solution in the Chinese Loess Plateau, a non-glaciated region, displayed lower values during glacials (loess formation) and higher values during interglacials (paleosol formation), which is modulated by temperature dominance of mineral weathering rate. Such contrasting weathering dynamics in glaciated and non-glaciated regions suggest that 87Sr/86Sr ratios of river water delivered into the ocean would be greatly buffered by the contrasting Sr release regimes within continents. This process may limit seawater 87Sr/86Sr variation within a narrow range on glacial-interglacial time scales and provide a novel indicator for tracing the onset of glacial development during the deep past.

How to cite: Yang, Y., Galy, A., and Fang, X.: Contrasting weathering dynamics within continents during the past glacial cycles, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-17150,, 2023.

Supplementary materials

Supplementary material file