|Figure A-8. Dolostone from Cambrian strata in Missouri. Both images are from one thin section of one hand sample, illustrating the variablity of fabrics in dolostones. Dolomite commonly grows as rhombic crystals (whereas calcite cleaves as rhombs but commonly grows in other forms). Arrows highlight examples of dolomite rhombs in each image. Dolostones are commonly believed to the result of alteration of limestones; this specimen appears to have been an intraclastic grainstone (a limestone) that was dolomitized.
Photomicrographs were taken in plane-polarized light; field of view of each is 1.3 mm wide; "P" indicates pores. Missouri Highway 8 Roadcut through Upper Cambrian Davis Formation east of Podosi, Missouri, U.S.A.; Sample PO3; thin section S- 1- 139. Sample collected by L. Bruce Railsback.
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