High-resolution sequence stratigraphy of clastic shelves IX: Methods for recognizing maximum flooding conditions in shallow-marine settings

Abstract

Maximum flooding conditions in high-frequency sequences are associated with a condensed section, a generally cryptic maximum flooding surface, and with facies contacts marked by grain size changes, shell beds and bioturbation; i.e., the downlap surface and the local flooding surface. Conditions of maximum water depth usually occur above the condensed section, in the early highstand systems tract. Due to its importance in sequence stratigraphic analysis, the identification of the precise position of the maximum flooding surface, which separates the transgressive and highstand systems tracts, is critical. This is particularly true in high-resolution studies based on field and core data, where only facies contacts that are older and younger than the maximum flooding surface are recognizable. An integration of several criteria, including sedimentological (facies analysis), diagenetic, micropaleontological, geophysical and geochemical, represents the best approach to define a relatively thin uncertainty interval within high-frequency sequences, in which the cryptic MFS should lie. Among the available criteria, those sedimentological and diagenetic are the ones best suited to recognize facies contacts, whereas those micropaleontological are the most reliable ones to identify the position of the maximum flooding surface. Future studies on the integration of these methods with those geophysical and geochemical have the potential to improve the ability to identify the maximum flooding surface, and improve the available tools in the high-resolution sequence stratigraphic analysis.