EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

A mechanism to explain the timing of glaciations related to orogenic episodes

Manoj Joshi and Benjamin Mills
Manoj Joshi and Benjamin Mills
  • University of East Anglia, Environmental Sciences, Norwich, United Kingdom of Great Britain and Northern Ireland (

Over very long timescales, mountain building or orogenesis is associated with increased weathering, the drawdown of atmospheric CO2, and global cooling. Considering the Phanerozoic glaciation in particular, a multimillion‐year delay appears to exist between peaks in low‐latitude mountain uplift and the maximum extent of glaciation, implying a complex causal relationship between them. We show, using a combination of physical climate/circulation modelling and geochemical modelling approaches, that global silicate weathering can be modulated by orogeny in three distinct phases. High, young mountain ranges experience preferential precipitation and the highest erosion. As mountain ranges denude, precipitation decreases, but runoff temperature rises, sharply increasing chemical weathering potential and CO2 drawdown. In the final phase, erosion and weathering are throttled by flatter topography. We hypothesise that orogeny acts as a capacitor in the climate system, granting the potential for intense transient CO2 drawdown when mountain ranges are denuded. Intriguingly, depending on the future evolution of the Tibetan Plateau, the mechanism suggests such a scenario potentially happening 10–50 × 106 years in the future.

How to cite: Joshi, M. and Mills, B.: A mechanism to explain the timing of glaciations related to orogenic episodes, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11136,, 2020


Display file