Zoned (defined by cathodoluminescence) cements. Zonation relates to increasingly reducing conditions of pore waters. Zoned cements in peritidal beds have complex zonations; these cements are meteoric vadose to shallow phreatic. Major cementation of subtidal facies occurred under burial conditions, and have a simple zonation reflecting progressive burial of the carbonate ramp. The distribution of nonluminescent cement defines the regional distribution of oxidizing portions of the paleoaquifer system.--Modified journal abstract.