CoachA carbonate ramp is a platform whose floor slopes gently and evenly from the shoreline into the basin, with no break: its facies belts, from tidal flats and beach-barrier sands to shoal grains, bioclastic sand and offshore lime mud, are wide and pass gradually into one another, sorted by the wave energy that decreases with depth. A rimmed shelf is a flat-topped platform with a marked break of slope at its margin, where reefs and sand shoals build a rim that shelters a lagoon behind it; beyond the rim a steep slope sheds blocks and grains into the basin.
