CSU GeoPAST Group

Spatial distribution of reconstructed δ18Op (a) and reconstructed δ18Op 1σ (b). (a) Comparison of reconstructed δ18Op from δ18Oc (large squares) calculated using the yearly mean of monthly long-term temperature data retrieved from NARR for each site. Modern meteoric water δ18O (small circles) is derived from modern groundwater, river water, or stream water. Data points are colored by their δ18O values. (b) The 1σ of the reconstructed δ18Op derived from the variability in the δ18Oc values from each stratigraphic section. In both panels, the black polygon marks the extent of modern-day exposure of the Ogallala Formation (from Manser et al. 2024).

Stream water δ18O (a) and d-excess (b) from across the Pamir range in eastern Tajikistan/western China. The decrease and then increase in δ18O and d-excess as one moves east across the Pamir results from a dramatic change in precipitation seasonality, modulated by orographic interactions with the mid-latitude jet (from Chen et al. 2025).