COMPARATIVE ANALYSIS OF SPECIES AND FACIES: A STUDY OF TWO PREVIOUSLY UNDESCRIBED FOSSIL CORAL REEFS, SAN SALVADOR ISLAND, THE BAHAMAS

At least fifteen fossil reef localities that originated during oxygen isotope stage 5 (approximately 135-75 ka) exist on San Salvador Island, The Bahamas, though only three have been intensively studied to date. Two of the unstudied reefs, Reckley Hill Pond and Holiday Track, were studied to determine their physical and biologic characteristics, and were then compared to previously studied fossil reefs at Grotto Beach and Sue Point as well as modern reefs throughout the island. Evidence suggests both Reckley Hill Pond and Holiday Track fossil reefs are patch reefs bearing close similarities to those ancient and modern reefs previously mentioned. Reckley Hill Pond's fossil reef outcrop was limited in its apparent exposure and species composition, however it is believed to have been preserved at a relatively younger stage of development. In contrast, Holiday Track fossil reef is a much larger and more biologically diverse outcrop consisting of in situ and boulder rubble components, both determined to be related constituents of the same patch reef. The depositional model of The Bahamas developed by Carew and Mylroie (1995) suggests Reckley Hill Pond and Holiday Track fossil reefs were roughly the same age, likely forming during oxygen isotope substage 5e approximately 132-119 ka. However, a radiometric age determination on a coral from Holiday Track indicates it may be several thousand years younger, 103 ± 4 ka (Carew & Mylroie, 1987), and is thought to have originated during substage 5c. Should further radiometric dating at Holiday Track suggest the fossil reef did in fact originate during substage 5c, the depositional model of Carew and Mylroie may require modification to include substage 5c's presence in the subaerial fossil record of The Bahamas in addition to substage 5e.