Constraints on Silicate Weathering Rates in Different Settings:Climatic or Tectonic?

Though there have been controversies concerning relationships among weathering rate and tectonic and climatic change, it is commonly recognized that chemical weathering of silicate minerals plays a substantial role in regulating the partial pressure of atmospheric carbon dioxide and thus in maintaining global surface climatic stability over the geological timescale. How to understand the constraints on chemical weathering of silicate minerals remains a major challenge, especially when any single climatic factors have been proved hard to interpret the long-term silicate weathering rate. Based on the compilation of chemical weathering rates of silicate minerals and physical erosion rates in different settings, this study shows that weathering rates and tectonic and climatic changes on different spatial and temporal scales have coupling or even conflicting relationships. Such results suggest that the silicate weathering rates cannot be explained in terms of merely a single process, and that the explanation requires a consideration of multiple factors. Although influence of tectonic uplift is suggested to serve as an important role on the change of silicate weathering, it may be cursory to link various changes on the Earth's surface in the Late Cenozoic to the stepwise uplift of the main orogenic belts, especially of the Himalayan—Tibetan orogen. In different settings, tectonic and climatic constraints on silicate weathering are not necessarily incompatible, especially on time scales of a few million years. Thus, the hypothesis proposed for “tectonic uplift—chemical weathering—climatic changes” is faced with a new challenge.