Figure F6. Typical Albian sandstone illustrating the effects of staining for feldspar recognition (Sample 210-1276A-49R-2, 130 cm). Grains outlined with dark golden yellow stain (also along cleavage) are potassium feldspar, pale pink grains are Ca-rich plagioclase feldspar, whereas more albitic grains are etched but not stained. A. Plane-polarized light. B. Cross-polarized light. Note the patchy birefringence exhibited by poikilotopic interparticle carbonate cement.

Figure F6. Typical Albian sandstone illustrating the effects of staining for feldspar recognition (Sample 210-1276A-49R-2, 130 cm). Grains outlined with dark golden yellow stain (also along cleavage) are potassium feldspar, pale pink grains are Ca-rich plagioclase feldspar, whereas more albitic grains are etched but not stained. A. Plane-polarized light. B. Cross-polarized light. Note the patchy birefringence exhibited by poikilotopic interparticle carbonate cement.