ABSTRACT
Diagenetic features in corals from Miocene silty marls in the coastal plain differ markedly from those in carbonate rocks. Fe-dolomite neomorphically replaced coral skeleton and early marine calcite cement, in addition was precipitated in remaining pore-space. Ferroan dolomite altered to dolomite and goethite or dissolved. Next followed goethite/hematite replacement and cement, then gypsum/anhydrite replacement and cement. Later ferroan calcite precipitated. Variations in pH/Eh and in porewater compositions (ions partially derived from dissolution of instable minerals) determined this sequence of shallow burial diagenesis.
