Fig. 2
From: Global analysis reveals climatic controls on the oxygen isotope composition of cave drip water
Global oxygen isotope relationships. a Global relationship between δ18Odripwater and δ18Oamountwprecip. The global data set regression line is shown in red: δ18Odripwater = 0.64 (±0.25) + 1.10 ( ± 0.04) δ18Oamountwprecip (‰). Sites are coloured according to their mean annual temperature and symbols show their region: Europe (squares), China (circles), Australia (diamonds), United States (triangles) and other (stars). b Frequency histogram for the global data set for the difference between δ18Oamountwprecip and δ18Odripwater (Δawp-dw). c Relationship between the δ18Orechargewprecip, δ18Oamountwprecip and δ18Odripwater for the European data set. The amount-weighted data are shown in open black symbols, and the regression line is shown in gray: δ18Odripwater = 1.19 (±0.59) + 1.20 (±0.08) δ18Oamountwprecip (‰). The recharge-weighted data are shown by coloured symbols (as for (a)) and the regression line is shown in black: δ18Odripwater = 0.06 (±0.50) + 1.01 (±0.06) δ18Orechargewprecip (‰). The arrows show the direct effect of recharge weighting. d Frequency histogram for the European data set for the difference between δ18Orechargewprecip and δ18Odripwater (Δrwp-dw) and δ18Oamountwprecip and δ18Odripwater (Δawp-dw) for the European data. Typical analytical uncertainties for individual δ18O analyses are ± 0.2‰42
