Extended Data Fig. 6: An enhanced early Pliocene/late Miocene zonal pH gradient is observed under different treatments of the data.
From: Pliocene decoupling of equatorial Pacific temperature and pH gradients
δ11B-derived pH from O. universa from the east (blue) and west (red) with 2σ uncertainty from a Monte Carlo simulation (empty circles; averages at ~1 Ma, ~3 Ma and ~6 Ma in filled circles) showing: all observations of modern pH used in producing average modern pH reference values (diamonds) given as individual dashes (a), the range of pH from using varied SST records in the pH calculation (grey bars) (b), pH as calculated using the SST record derived from calibrating this study’s Mg/Ca data with the BAYMAG calibration88 (c), and pH as calculated using dissolution-corrected118 Mg/Ca SSTs from this study (yellow squares) (d). In panel b, pH ranges cover pH calculated using: TEX86-derived3 SSTs, Mg/Ca-derived SSTs (this study) using a linear correction for Mg/CaSW, and Mg/Ca-derived SSTs (this study) using a power-law correction87 for Mg/CaSW. Both Mg/Ca-SST calibrations were done using the Mg/CaSW record of Fantle and DePaolo81.
