Neutron-Induced Fission of Uranium: A Dating Method for Lunar Surface Material

Science  14 Jan 1983:
Vol. 219, Issue 4581, pp. 170-172
DOI: 10.1126/science.219.4581.170


Volcanic glasses collected on the rim of Shorty Crater in the Apollo 17 area were formed 3.63 x 109 years ago. The amounts of xenon-136 produced by neutron-induced fission of uranium-235 indicate that the glasses resided on the lunar surface for about 38 million years before they were deeply buried. The glass spherules were reexcavated by the impact that formed Shorty Crater 17 million years ago, and remained undisturbed until they were collected.