Carbonate environments

Distribution of Facies: RimmedCarbonate shelves• Distinct break in slope from shallower inner shelf to outer zone. Thispoint is very high energy, receiving the full force of wave and stormenergy. (Hermatypic corals here, away from muddy input) Theseform barrier reefs. (can also have oolitic/ skeletal buildups here).• Behind barrier is the shelf lagoon. Low energy.a) Closed lagoon-limited circulation. Lime mud. +/- hypersaline=restricted fauna. +/- Sabkha.b) Open lagoon- subject to tides and waves. Higher energy (shoals,lenses grain/packstone) Coarse facies are commonest on the sideof lagoon nearest to reef as material is reworked from the reed intothe lagoon.Coastal facies are low energy tidal flats (usually), beach barriers candevelop if enough energy.