Abstract
Deep Earth degassing is a critical forcing factor for atmospheric CO(2) variations and palaeoclimate changes in Earth's history. For the Cenozoic, the key driving mechanism of atmospheric CO(2) variations remains controversial. Here we analyse three stages of collision-related magmatism in Tibet, which correspond temporally with the three major stages of atmospheric CO(2) 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 CO(2) emission flux associated with the evolving Neo-Tethyan to continental subduction over the Cenozoic. The correlation between our modelled CO(2) emission rates and the global atmospheric CO(2) curve is consistent with the hypothesis that the India-Asia collision was the primary driver of changes in atmospheric CO(2) over the Cenozoic.