On the left, a plane-polarized light image of a quartz sandstone. On the right, a color scanned CL image of the same area. An anastomosing macrofracture cuts through this sample. In the CL image, the quartz cement overgrowths and the crack-seal texture are immediately apparent. Some of the microfractures are visible in the PPL image because they are marked by fluid inclusion planes, but the CL image brings out detail otherwise invisible. Sample is Cretaceous Travis Peak Fm.

On the left, a cross-polarized light image of a quartz sandstone. On the right, a color scanned CL image of the same area. An anastomosing macrofracture cuts through this sample from top to bottom. In the CL image, the quartz cement overgrowths and the crack-seal texture are immediately apparent. Some of the microfractures are visible in the PPL image because they are marked by fluid inclusion planes, but the CL image brings out detail otherwise invisible.

On the left, a gypsum-plate-modified, cross-polarized light image of a quartz sandstone. On the right, a color scanned CL image of the same area. An anastomosing macrofracture cuts through this sample. In the CL image, the quartz cement overgrowths and the crack-seal texture are immediately apparent. Some of the microfractures are visible in the PPL image because they are marked by fluid inclusion planes, but the CL image brings out detail otherwise invisible.

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