The study of fission track and other crystalline defects using confocal scanning laser microscopy

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Abstract
Summary: Confocal scanning laser microscopy (SLM) is a technique that offers geologists a new way of studying structures in minerals at the submicrometre level. As an example we show how the non‐destructive nature of confocal SLM can be used to measure and count fission tracks (line defects formed by the spontaneous fission of238U) in the uranium‐bearing mineral apatite, and to provide information about the geometry and crystallographic orientation of fluid inclusions trapped inside apatite grains during crystallization. The technique also provides a means of studying the internal geometry of chemical zonation in minerals. The digitized nature of the SLM images makes them amenable to a variety of image analysis techniques, and we show how image analysis can be used to measure fission tracks in mica sheets and provide crude estimates of track dip. Finally, using a chemically etched mica sheet we show how confocal SLM can be used to provide a detailed near‐surface (1–5 μm) analysis of geological materials.