Fig. 4: Correlations between δ¹³C_DIC and riverine ion ratios.

The molar ratios of (a) SO₄/HCO₃; b HCO₃/(Ca+Mg); c Si/HCO₃, of the large rivers in the Tibetan Plateau. The end-member of rock weathering is referenced to Refs. ^16,51,52. The data for the Ganges-Brahmaputra, Brahmaputra, Krishna, Beipan, and Wujiang Rivers are from refs. ^{26,52,53,54,55}.