Zircon Zonation Patterns with CL
Panchromatic cathodoluminescence imaging of zircon growth zonation
Similar to growth rings in trees, growth zonation yields chronological information about the geological formation of zircon. The cathodoluminescence (CL) emission from a rock gives insights into crystal growth, zonation, cementation, replacement, deformation, provenance, trace elements and defect structures. This can be used to fingerprint rocks and reveal interesting spatial textures on a submicron scale.
The power of cathodoluminescence is the combination of functional optical information with the high spatial resolution of electron microscopy. Thus CL imaging is an ideal tool to study geological samples like the zircon (ZrSiO4) sample shown:
SEM image of zircon (left) and corresponding CL image (right) showing zonation patterns
Samples courtesy of Prof. Jens Jahren (University of Oslo)
Because CL imaging is highly sensitive to small concentration variations in trace elements such as rare-earth ions, CL data often provide information unattainable by standard scanning electron microscopy (SEM) techniques. CL imaging is also a useful pre-screening tool for secondary ion mass spectrometry (SIMS) used to investigate zonation patterns.