India-Asia collision as a driver of atmospheric CO₂ in the Cenozoic.

Abstract

Deep Earth degassing is a critical forcing factor for atmospheric CO₂ variations and palaeoclimate changes in Earth's history. For the Cenozoic, the key driving mechanism of atmospheric CO₂ variations remains controversial. Here we analyse three stages of collision-related magmatism in Tibet, which correspond temporally with the three major stages of atmospheric CO₂ variations in the Cenozoic and explore the possibility of a causal link between these phenomena. To this end we present geochemical data for the three stages of magmatic rocks in Tibet, which we use to inform a model calculating the continental collision-induced CO₂ emission flux associated with the evolving Neo-Tethyan to continental subduction over the Cenozoic. The correlation between our modelled CO₂ emission rates and the global atmospheric CO₂ curve is consistent with the hypothesis that the India-Asia collision was the primary driver of changes in atmospheric CO₂ over the Cenozoic.