Pleistocene patch reefs and Holocene swamp morphology, Grand Cayman Island, West Indies.

Non-mangrove vegetation is localized on emergent 'dry cays' within the mangrove swamps of Salt Creek. Lithological and palaeontological evidence suggests that these bedrock protrusions may be interpreted as a series of Pleistocene patch reefs which were initially slightly elevated above a sandy and silty lagoon floor. The Pleistocene bedrock is overlain by a laminated crust of subaerial origin, above which are Holocene sediments consisting of a localized basal orange mud and an overlying cover of mangrove-derived peat. This sequence from subaerial to intertidal sediments records the Holocene marine transgression of the area. Pleistocene patch reefs are at present emergent features, but would be submerged and covered by sediments if the transgression were to continue. -from Authors