Erasure of fission tracks in glasses and silicates by shock waves

Abstract

Shock loading experiments have been carried out to determine the effect of dynamic pressures and associated temperatures on fission tracks in tektite (indochinite) and soda-lime glasses, biotite, and apatite. Below shock pressures of 83 ± 4 and 31 ± 3 kb, track densities remain unaltered in the tektite and soda-lime glass, respectively. In the tektite glass, partial and complete erasure of tracks is observed in samples recovered from 112 ± 2 and 133 ± 10 kb. In the soda-lime glass, partial erasure is observed in samples recovered from 33 ± 3 and 42 ± 3 kb. Shock temperature calculations indicate that the temperatures achieved upon shocking the glasses are appreciably lower than those at which tracks would be annealed out under static conditions. Single-crystals of apatite retain tracks when shocked to 45 ± 5 kb. apatite recovered from shock pressures above 82 ± 5 kb is granulated to micron-sized particles which preclude recognition of tracks. Single-crystal biotite specimens shocked to pressure up to 173 ± 5 kb show no appreciable loss in fission track density.

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