WHERES THE REEF - THE ROLE OF FRAMEWORK IN THE HOLOCENE

Holocene reef models generally emphasize the role of in-place and inte rlocking framework in the creation of a rigid structure that rises abo ve its surroundings. By extension, a number of ancient biohermal depos its have been disqualified as ''true reefs'' owing to their lack of re cognizable framework. Fifty-four cores from several eastern Caribbean sites (Fig. 1) clearly demonstrate that in-place and interlocking fram ework is not common in these reefs that are comprised of varying mixtu res of recognizable coral (primary framework), loose sediment/rubble a nd secondary framework made up mostly of coralgal fragments bound toge ther by submarine cementation and biological encrustation. Recovery of primary and secondary framework ranged from 22% (avg.) in branching-c oral facies to 33% in intervals dominated by head corals. Accretion ra te decreased as expected with water depth However, the recovery of rec ognizable coral generally increased with water depth, inversely to pre sumed coral-growth rates. This pattern reflects a spectrum in the rela tive importance of coral growth (primary construction), bioerosion, hy dromechanical breakdown and the transport of sediment and detritus. Th e relative importance of each is controlled by the physical-oceanograp hic conditions at the site of reef development and will dictate both t he architecture of the reef and the character of its internal fabric. We do not propose that framework reefs do no exist, as they most assur edly do. However, the fact that so many modem reefs are not dominated by in-place and interlocking framework suggests that its use as the pr imary determinant of ancient reefs may be unreasonable. We, therefore, propose the abandonment of framework-based models in favor of those t hat treat framework generation, physical/biological degradation, sedim entation, and encrustation as equal partners in the development of mod ern and ancient reefs alike.