Constraining mantle carbon: CO2-trace element systematics in basalts and the roles of magma mixing and degassing

In light of our results, we reassess existing melt inclusion datasets, and find they exhibit systematics associated with partial degassing and mixing. We argue that all the data presently available is consistent with a depleted mantle CO2/Ba ratio of ∼140, and there is as yet no evidence for heterogeneity in the CO2/Ba ratio of the depleted mantle.