Using Carbon Isotope Equilibrium to Screen Pedogenic Carbonate Oxygen Isotopes: Implications for Paleoaltimetry and Paleotectonic Studies

Figure 6

Plot of δ¹³C_carb versus Δ¹³C. The grey box spans Δ¹³C values +13.4–17.84‰, which reflects the measured mean Δ¹³C value of +15.62‰ ±2σ (2.22‰). The solid black line reflects the slope of all carbonates formed from one-, two-, and three-components of CO₂ from Tabor et al. [6]. The data from Cotton et al. [26] are given by black stars and represent either carbonates formed under extremely evaporatively enriched conditions in terms of meteoric water or from three-component CO₂. In this case, because the entire stratigraphic section is calcite-cemented (grey dashed line; δ¹³C_carb = −3.2 ± 0.2‰) and the calcite cement is isotopic indistinguishable from the pedogenic carbonates, one would conclude that the pedogenic carbonates reflect this inheritance or recrystallization.