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

Figure 1

Plot of δ¹⁸O_carb for the past 75 Ma from Montana and Idaho. Data are from Chamberlain et al. [22]; age assignments reflect the assignments in the original data set; however, it should be noted that some of the individual sites have been redated subsequently (e.g., [47]). Shown in green is the maximum potential uplift between ~50 and ~30 Ma ago, and in blue, a conservative estimate based upon long term means before and after a regional unconformity between 32 and 24 Ma ago. Uplift estimates are based upon the global δ¹⁸O lapse rate of Poage and Chamberlain [18].