Radiation history of lunar microbreccias and lithic chrondrules from Weston meteorite by track data

Tracks generated in the lithic chondrules of the brecciated Weston meteorite as well as in the lunar microbreccias by iron group nuclei of solar cosmic rays are studied. The results for about 2000 olivine and pyroxene grains contained in 67 lithic chondrules indicate that a relict irradiation of the material occurred at an early stage in solar system formation, i.e., before these chondrules were assembled. The results for about 1000 olivine and pyroxene grains in 13 microbreccias strengthen our earlier conclusion that part of the chondrules from the Weston meteorite may have formed in processes analogous to brecciation. The newly obtained data confirm that the formation processes of the Weston lithic chondrules, containing solar flare irradiated crystals, were similar to the impact formation of microbreccias on the lunar regolith without heating compacted material up to temperatures of 6000-700 0C