Preliminary data from an investigation of tracks in olivine crystals, separated from the five zones of a lunar surface material core, are reported. The gradients of track densities, their lengths, and their angular distribution were measured with an optical microscope. Throughout the core depth (35 cm) crystals bearing traces of exposure to low energy solar cosmic rays were found, indicating the occurrence of mixing processes in the surficial layer of lunar surface material. The age of the occurrence of the samples investigated on the lunar surface, calculated from the track density, is in the interval 0.7 to 16 million years.
LUNAR AND PLANETARY EXPLORATION
Lunar Soil from the Sea of Fertility (NASA-TT-F-15881); p 379-387