T24 Three Billion Years of Reef Evolution I

Sunday, 27 October 2002
8:00 AM - 12:00 PM

WERE THERE CORAL COMMUNITIES IN THE CARIBBEAN DURING THE EOCENE?

Paper number: T24-15
Program: Technical Sessions
Time: 11:30 AM – 11:45 AM

Authors

Abstract

Reefs and coral rich deposits are comparatively rare in Eocene rocks from the Western Atlantic and Caribbean region. Regional reef coral diversity is also lower at this time than in any subsequent part of the Tertiary or Quaternary. Unfortunately, extensively collected fossil coral assemblages from the Caribbean Eocene are scarce, making it difficult to adequately define total species richness or to describe possible reef coral associations from this interval. The present work re-evaluates early Tertiary Caribbean faunas using new records from the early through late Eocene of Jamaica (Yellow Limestone Group and White Limestone Group) and from the middle-late Eocene of Florida combined with earlier published data from throughout the region.

The new data only slightly increases the total species richness for the Eocene. Richness for individual localities and lithostratigraphic units remains low. However, when considering distinct time slices within the Eocene, variation between localities and between formations is relatively high compared to data from younger rocks in the Caribbean. Comparison of ordination results also suggests significant differences between Eocene and younger coral faunas. Ordination of faunal records from Oligocene and younger rocks often displays associations of species grouped into assemblages of massive, platy or branched shaped corals. Eocene records show no such clear associations and distinct assemblages or communities are not easily defined.

It appears that Caribbean Eocene coral communities, if they existed at all, were less structured and perhaps more ‘open’ than those commonly recorded from the Oligocene through Recent. It remains to be seen whether this is the cause or the consequence of the general lack of Caribbean coral reefs during the Eocene.