Comparison of the NanoSIMS data on OR8 (filled green circles) and the IF8 mixing lines derived from the mixing model. Columns 1, 2 and 3 show the ¹⁵N/¹⁴N vs, ¹³C/¹²C, ¹⁵N/¹⁴N vs D/H and ¹³C/¹²C vs D/H compositions, respectively. Row a: mixing lines for α_N = α_C = α_H = α. The value of α is indicated by the blue to red color contours. IF mixing lines with varying labeled layer compositions are displayed with dashed lines. The composition of the unlabeled ice is indicated in gray. Row b: the composition of IF8 is fixed and the mixing factors α_N, α_C, α_H are free parameters. The value of the mixing factors are given by the gray scale on the top and right axes. The nominal mixing lines are plotted with bold dotted lines.