Cathodoluminescence Images

Cathodoluminescence (CL) is a powerful, but underutilized tool for many disciplines in geology including structural geology. It can provide information not obtainable through transmitted light microscopy. Microstructures not visible in plane or cross polarized (PL) light can be seen in superb detail in CL. The purpose of this page is to show some of the potential for CL. All photomicrographs were taken on a Techynosyn Cold Cathode Mark V system operating at 20-25 kV. Most samples are photographed in both CL and PL to allow comparison of the two methods and to highlight the differences. Long dimension in each photomicrograph is about 2 mm.

Cathodoluminescence	Polarized Light	Description
		Zoned calcite and saddle dolomite in boxwork breccia. Devonian-Mississippian Ouray-Leadville Fm., Silverton, CO.
		Zoned calcite and saddle dolomite in boxwork breccia. Devonian- Mississippian Ouray-Leadville Fm., Silverton, CO.
		Limestone breccia (medium red in CL) cemented with calcite (bright red in CL) and quartz (dull in CL). Euhedral quartz (seen in PL) indicates growth into cavity. Devonian- Mississippian Ouray- Leadville Fm., Silverton, CO.
		Quartz textures in boxwork veins including chalcedony (blurry texture in CL and radial fibrous in PL) and megaquartz (euhedral zoned xls in CL). Late veins cut from lower left to upper right. Brassy yellow-green luminescence is unusual for quartz. Cambrian Ignacio Fm., Silverton, CO.
		Zoned vein quartz showing band of chalcedony (fibrous in CL and PL). Quartz shows both concentric growth zoning and sector zoning. Cambrian Ignacio Fm., Silverton, CO.
		Silicified breccia. Breccia fragments are not readily visible in PL, but are obvious in CL. Field and petrographic evidence suggest rock was originally a carbonate breccia and that silica replaced calcite and dolomite. Devonian- Mississippian Ouray- Leadville Fm., Silverton, CO.
		Microveins in framework quartz grains showing different luminescence than grain or pore-filling quartz cement. Polarized light view on right shows no evidence of microveins. Lower Silurian Massanutten Sandstone, northern Virginia.
		Deformation lamellae (sub-parallel white lines) in framework quartz grain that cross from grain into pore-filling cement. This shows that lamellae post-date lithification and are not inherited from source terrane. Lower Silurian Massanutten Sandstone, northern Virginia.

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