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FERROAN AND NON-FERROAN CALCITE: Up. Permian (Kazanian?) Wegener Halvo Fm., Jameson Land, East Greenland Although most burial-stage cements are uniformly ferroan, reflecting the stability of most subsurface settings, that statement has numerous exceptions. Many burial cements, especially ones associated with highly permeable fracture or vug systems, show repeated geochemical fluctuations. This fracture, for example, is filled with successive bands of ferroan (blue stain) and non-ferroan (pink stain) calcite indicative of major fluctuations in redox conditions of pore fluids during precipitation. The final ferroan calcite cement contains hydrocarbon traces. Chapter 22: CARBONATE DIAGENESIS: Meo- and Telogenetic Burial Diagenesis; p. 367. Memoir 77: A Color Guide to the Petrography of Carbonate Rocks: Grains, textures, porosity, diagenesis by Peter A. Scholle and Dana S. Ulmer-Scholle
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FERROAN AND NON-FERROAN CALCITE: Up. Permian (Kazanian?) Wegener Halvo Fm., Jameson Land, East Greenland Although most burial-stage cements are uniformly ferroan, reflecting the stability of most subsurface settings, that statement has numerous exceptions. Many burial cements, especially ones associated with highly permeable fracture or vug systems, show repeated geochemical fluctuations. This fracture, for example, is filled with successive bands of ferroan (blue stain) and non-ferroan (pink stain) calcite indicative of major fluctuations in redox conditions of pore fluids during precipitation. The final ferroan calcite cement contains hydrocarbon traces. Chapter 22: CARBONATE DIAGENESIS: Meo- and Telogenetic Burial Diagenesis; p. 367. Memoir 77: A Color Guide to the Petrography of Carbonate Rocks: Grains, textures, porosity, diagenesis by Peter A. Scholle and Dana S. Ulmer-Scholle