Carbonate Cements and Authigenic Precipitates
2015. "Carbonate Cements and Authigenic Precipitates", A Color Guide to the Petrography of Sandstones, Siltstones, Shales and Associated Rocks, Dana S. Ulmer-Scholle, Peter A. Scholle, Juergen Schieber, Robert J. Raine
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Carbonate minerals, particularly calcite, dolomite, ankerite and siderite, are important as cements and replacements in sandstones and mudstones. Perhaps surprisingly, carbonate cements can be difficult to work with in terms of quantifying conditions of formation (including time, temperature and water chemistry). There are two reasons for this. First, some carbonate minerals (especially dolomite in the context of cements in clastic terrigenous deposits) can recrystallize at one or more stages, resetting their diagnostic fabrics and elemental and isotopic composition. Second, all carbonate cements are relatively soft minerals with multiple cleavages. That means that fluid inclusions, when subjected to temperatures higher than those at which they formed, can stretch or leak, resetting apparent temperatures of formation (Goldstein, 1986 and 2001). That said, there is abundant evidence that carbonate cements form at virtually any stage of diagenesis, from synsedimentary to deep burial (see overview in Morad, 1998).
Figures & Tables
AAPG Memoir 109 is designed as a practical guide for students and professionals to learn the fundamentals of microscopic examination of sandstones, mudrocks, and associated rocks. With more than 1100 color illustrations, it covers the identification of grains, textures, and structures of clastic terrigenous rocks as well as their diagenetic alteration (compaction, cementation, dissolution, and replacement) and porosity reduction or enhancement. It also provides classification diagrams for formal description of those rocks and their porosity. Although the majority of the outcrop and subsurface examples come from the United States (35 states and Puerto Rico), there are representative photographs from 32 other countries, including many from the offshore areas. The foldout birefringence chart and an included DVD with Powerpoint files of all of the petrographic images provide additional aids for instructors and students.