Experiments to determine if the presence could be confirmed of excess 14C implantation in lunar soils and a rock surface sample were undertaken. Stepwise HF etchings of near-surface lunar soil 73221, collected from 0 to 0.5 cm depth and surface soil 10084, and a sample of surface scrapings from rock 68815 released appreciable amounts of 14C. Considering the amount of material dissolved, we find that the amounts of 14C released are significantly in excess of the amounts that would be necessary for both galactic and solar cosmic-ray-produced 14C, even for the very surface. Further, there is an excess of 14C released compared to deeper samples of rock and soil, based on our analyses of subsurface soils (73241 and 73261) from the same trench location of 73221, and earlier studies of 14C in rock 68815. Based on the observed release pattern of 14C, we estimate that the excess 14C in the lunar surficial samples may be released from depths of up to several microns. We conclude that this is an implanted solar component.
ASJC Scopus subject areas
- Geochemistry and Petrology
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science