Figure 1
Plots of carbon, oxygen isotope ratios, Δ47, temperatures of carbonate precipitation and estimated water isotopic composition with age (time of deposition) are shown.
(a) Average carbon isotope ratios from replicate samples, (b) Average oxygen isotope ratios from replicate samples and (c) Average Δ47 measured from replicate samples of soil carbonates obtained from the different strata of varying ages with error bar marking 1σ around mean values. Data from earlier work8,15,16,17,18 are also shown for comparison (d) Average temperature estimates for soil carbonate precipitation estimated from the measured Δ47 values by using the relationship given by Ghosh et al.14 and later revised by Dennis et al., (2012) (e) Estimated δ18O of soil water in an equilibrium condition plotted with age. Temperature and δ18O of carbonate measured in this study were used as input parameters in the oxygen isotope thermometry18 equation to obtain the values.
