In order for fossil data to be meaningful for interpretation of paleocommunities and paleoenvironments, understanding the changes experienced by skeletal material between death and fossilization is essential. Coral rubble samples collected from three reefs growing in differing wave energy environments adjacent to San Salvador, Bahamas were analyzed to determine the degree of skeletal alteration by encrusting and bioeroding
organisms, abrasion, and dissolution. Initial results reveal both differences and similarities to previously published coral taphonomy research.
The most important factors influencing alteration of modern coral rubble seem to be growth environment and colony growth form: 1) Rubble accumulating at the low energy site exhibited better preservation than did the rubble from both intermediate and higher energy sites. This finding contrasts with results from both the Great Barrier Reef and the Florida Keys; 2) A positive correlation between encrusting and boring organism diversity and interactions also exists with environmental energy; and 3) Corals of massive colony growth form were most highly degraded by boring organisms followed by branching growth forms, as shown by previous studies. However, branching corals were most physically and chemically degraded, in contrast to other studies.
These results suggest that care must be taken when making paleoenvironmental conclusions based upon taphonomic alteration of fossil material. Some variables, such as growth form may exhibit some consistency over geographically widespread areas. Conversely, environmental energy may cast different taphonomic signatures from region to region, indicating that other, more important controls may be operating within certain reef environments.
Jill Bries, ’99 Cottage Grove, MN
Majors: Geology, Environmental Studies
Sponsor: Benjamin Greenstein