Depth profiles of Mn-53 in lunar rocks and soilsResults of measurements of cosmic-ray-produced Mn-53 taken down the length of the Apollo 16 deep drill core are presented. They indicate that the lunar regolith has been unmixed, on a meter scale, for the past 5 million years at the location of this core. The data are in agreement with earlier Mn-53 measurements on the Apollo 15 drill core. Mn-53 activity profiles in 14310, 12002, and 14321 are compared to each other; all three rocks have probably been on the lunar surface long enough to saturate their solar cosmic-ray-produced Mn-53 (half-life = 3.7 m.y.) activity.
Document ID
19750055599
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Imamura, M.
Nishiizumi, K.
Honda, M. (Tokyo, University Tokyo, Japan)
Finkel, R. C.
Arnold, J. R.
Kohl, C. P. (California, University La Jolla, Calif., United States)