Fig. 2: Water chemistry in relation to the expected chemical signatures of critical-zone weathering and metamorphic carbon. | Nature Geoscience

Fig. 2: Water chemistry in relation to the expected chemical signatures of critical-zone weathering and metamorphic carbon.

From: Deep CO2 release and the carbon budget of the central Apennines modulated by geodynamics

Fig. 2

a,b, Ratios of [Ca2+]/[Σ+] plotted against ratios of [SO42−]/[Σ+] for winter samples (a) and summer samples (b). c,d, δ13C plotted against F14C for winter samples (c) and summer samples (d). Samples are coloured by the dominant lithology in the upstream area21: carbonate, mixed carbonate and siliciclastic, or siliciclastic. Bars represent ion or isotopic endmember compositions21. Annotated samples in a and b are samples with low [Ca2+]/[Σ+] that have higher [Na+] than [Ca2+] and reflect evaporite δ34S and δ18O(SO4) signatures.

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