Himalayan-Tibetan Erosion Is Not the Cause of Neogene Global Cooling

Uplift and erosion of the Himalayas and Tibetan Plateau have resulted in the deposition of some of the largest sedimentary masses on Earth. Chemical weathering of these materials has been invoked as a primary driver of long-term global cooling because weathering of silicate material consumes atmospheric CO2. We here combine geochemical data from scientific drill sites in the Arabian and South China Seas, together with sediment mass flux budgets, to estimate changes in chemical weathering fluxes for the Indus, Mekong, and Pearl river systems. The rate of CO2 consumption decreased by 50% between similar to 16 and 5.3 Ma, especially in the Indus system, as onshore erosion slowed and provenance shifted away from mafic arc units in the suture zone. Falling chemical weathering fluxes during a period of global cooling refutes the idea that Himalaya-Tibetan Plateau uplift drove Neogene global cooling.

Automated summary

The study indicates that the chemical weathering flux in the Himalayas and Tibetan Plateau decreased by 50% during a certain period, especially in the Indus river system, contradicting the idea of global cooling during that time.