Figure A-6. Oolitic limestone (specifically, an oolitic grainstone) with calcite cement. Grains are ooids (O) and skeletal grains (S) with oolitic coatings. Note abundant small crystals of early cement (arrows) that have grown from the edges of pores. The ooids consist of innumerable small calcite crystals that provided lattices from which pore-rimming cements grew. In contrast, the center of each pore is filled with only one or two large calcite crystals (C).
     Many more photomicrographs of limestones are available in Scholle's (1978) "A Color Illustrated Guide to Carbonate Rock Constituents, Textures, Cements, and Porosities".
     Photomicrograph was taken in parallel-polarized light (polarizer parallel to analyzer); field of view is 2.0 mm wide. Jurassic grainstone from near Tunnel du Legionnaire, Ziz Valley, High Atlas Mountains, Morocco; Sample JM9-18F; thin section S-1-138. Sampled collected by L. Bruce Railsback and Joseph Walsh.
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