Figure 1 : Δ47 measurements in modern eggshells.

From: Isotopic ordering in eggshells reflects body temperatures and suggests differing thermophysiology in two Cretaceous dinosaurs

Figure 1

Data from modern bird and ectotherm eggshells are plotted against published inorganic calcite calibrations. Data are given in Table 1 and temperature calibrations in Supplemental Note 2. By convention temperature is plotted as 106/T2 (T in Kelvin) on the x axis, but we indicate T in °C at the top of the plot. Linear regressions on the absolute reference frame were calculated as described previously28. Eggshell data and linear regression match more closely with the calibrations produced in the Caltech of Ghosh et al.19, and the Caltech all biogenics calibration of Eagle et al.26, than with that of Tang et al.41 (Supplemental Note 2). The slope of the regression through eggshell data is described as: Δ47=0.0493±0.0043 (106 T−2)+0.1393±0.0447.