Fig. 1.
NanoSIMS ion images of the D/H ratio. The 20 × 20 μm2 images are expressed in δD units relative to the D/H ratio of the bulk sample (for comparison purposes, color scale bars for δD all range between −1,000 and +4,000‰). (A and B) Data collected from the same image of IOM produced from a CH4 plasma, illustrating the routine quality of imaging the D/H ratio. (A) H intensity is expressed in counts per second. The H variations reflect the H ionic emissivity related to the topography of the sample surface. (B) The statistical δD distribution is shown for an isotopically homogeneous area. The statistical error on the average δD value for this image was ±30‰ (1 SD). At the pixel level of the image, the variations in δD are unrelated with H intensity, ruling out any possible topographic effect on the determination of δD values. (C) Contrary to the homogeneous δD distribution commonly observed in terrestrial samples and standards, the IOM collected from CH4 plasma exhibits δD heterogeneities in some rare areas rich in hot spots. (D) Example of the IOM isolated from the Murchison meteorite exhibiting hot spots [bulk IOM δDSMOW = +970‰ (5); NanoSIMS data are from ref. 19].