Stratigraphic interpretation of submarine versus subaerial discontinuity surfaces: An example from the Cretaceous of Texas

Studies of modern carbonate sediments indicate that submarine cementation is a widespread, on-going process, and that sediments cemented recently beneath the sea are now being eroded by marine currents and bored by marine organisms. By analogy, many ancient carbonate rocks may have been cemented in a similar way, and many discontinuity surfaces, corrosion zones, or “hard grounds” may have formed under submarine conditions. The interpretation of discontinuity surfaces in the Edwards Formation (Lower Cretaceous) of Texas as submarine, rather than subaerial, in origin leads naturally to wide differences in correlation, Stratigraphic interpretations, quantitative map values and interpreted geologic history. Features of vertical and lateral rock sequences, and regional relationships can help distinguish submarine from subaerial discontinuity surfaces.