Figure F6. Photomicrograph of calcite-cemented glauconitic silty medium sandstone under cross-polarized light (Sample 313-M0028A-25R-1, 5–10 cm). Quartz grains are subrounded to subangular, with some surfaces rimmed by glauconite. Calcite cement occurs as microspar. Opaque grains are scattered within the cement and concentrated along the fringe of and within glauconite grains. Large dark green glauconite grain on right shows irregular lobate morphology. Pale green glauconite grain on left has irregular shape and is surrounded by sparry calcite. Field of view = 0.7 mm.
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