Repetitive reef to ooid sequences near leeward margin of Caicos Platform, British West Indies
Drill core transects and outcrops near the leeward margin of the Caicos Platform, BWI, reveal repetitive (one Holocene and two Pleistocene) shallowing-upward sequences of either (a) reefal boundstones overlain by layered oolitic grainstones or (b) burrowed oolitic grainstones overlain by layered oolitic grainstones. Each sediment sequence is separated from the other by a calcrete exposure surface. A transect, perpendicular to the trend of an exposed Pleistocene barrier reef/ooid sand complex, shows two separate sediment packages of reefal boundstones and reef-derived skeletal packstones overlain by layered oolitic grainstones. The well-exposed upper package consists of a shallowing-upward barrier reef, which is immediately overlain by burrowed and cross-bedded oolitic grainstones, beach rock blocks, and coral rubble, capped by layered oolitic grainstones. Separated by an exposure horizon, the lowermost package consists of coral and skeletal sands overlain by layered oolitic grainstones. Cores from a transect in a non-reefal setting north of the barrier reef complex reveal highly burrowed oolitic grainstones capped by layered oolitic grainstones. As a Holocene example, immediately offshore of this transect, modern reefs and bioturbated oolitic grainstones are presently being buried beneath coral rubble, beach rock blocks, and prograding oolitic beaches. Deposition of the capping layered oolitic grainstones appears to occur during stable and falling sea levels. This co-occurrence of reefal sediment and ooid sands suggests that the two are not mutually exclusive and that reef-ooid succession is a reoccurring part of leeward margin platform margin-building.
- Research Organization:
- Univ. of Miami, FL
- OSTI ID:
- 5865875
- Report Number(s):
- CONF-870606-
- Journal Information:
- AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States), Journal Name: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States) Vol. 71:5; ISSN AABUD
- Country of Publication:
- United States
- Language:
- English
Similar Records
Quaternary sedimentation and diagenesis in a high-latitude reef, Houtman Abrolhos Islands, Western Australia
Expanded model for ooid form and genesis: Caicos platform, British West Indies