COMPARATIVE ANALYSIS OF FOSSIL REEFS ON SAN SALVADOR ISLAND, BAHAMAS: SIMILIARITIES AND DIFFERENCES IN SPECIES AND FACIES

A few fossil coral reefs localities on San Salvador Island, Bahamas have been the focus of research during the past 20 years, but only two have been studied intensively (and separately), whereas several fossil reefs remain relatively unstudied. The primary objectives of this study are to test hypothesized correlations of previously studied fossil reefs and compare these to fossil reefs elsewhere on the island. Five fossil reefs were investigated, using the Cockburn Town and Grotto Beach fossil reefs as benchmarks for comparison because of extensive prior research and variant species compositions at these localities. The three remaining fossil reefs (Field Station, Holiday Track, and Storr’s Lake Narrows) were compared to the Cockburn Town and Grotto Beach reefs. The Cockburn Town reef is dominated by the corals Acropora palmata and A. cervicornis and lesser amounts of Montastrea, Diploria, and Porites; this deposit is interpreted as a bank-barrier reef. In contrast, Grotto Beach reef lacks Acropora and is instead dominated by the corals Porites, Diploria, and Montastrea, and is capped by coralline algae (e.g., Neogoniolithon). This reef is interpreted as a patch reef. The Cockburn Town and Grotto Beach reefs demonstrate shallowing-upward sequences, have similar species compositions, and show similar ages, placing their origin during the Sangamonian sea-level highstand (118,000-130,000 B.P.). Accordingly, the Holiday Track and Storr’s Lake Narrows reefs are predicted to be represented by similar fossil species and facies. Although Field Station fossil reef may also have characteristics similar to the other four reefs, its greater distance from the present-day shoreline in comparison to the other four reefs may lend to variant characteristics.