2002 Denver Annual Meeting (October 27-30, 2002)

Paper No. 3
Presentation Time: 1:30 PM-5:30 PM


DRUMMOND, Carl N. and HOVERMAN, Robert, Department of Geosciences, Indiana Univ Purdue Univ Fort Wayne, Fort Wayne, IN 46805, drummond@ipfw.edu

Colonies of Halysites coral make up one of the most important components of reef-margin framestone found within carbonate build-ups of the Huntington Member of the Silurian Wabash Formation of northeast Indiana. Partial to complete silicification allows for their separation from the dolo-mudstone matrix such that two- and three-dimensional geometry is easily observed. Small to medium sized colonies (2-30 cm diameter) display the distinctive cateniform geometry characteristic of Halysites. Pseudo-hexagonal lacunae are defined by corallites joined at triple junctions. Such junctions are typically separated by one to four corallites defining sublinear to irregular serial chains. Two-dimensional geometries of coral colonies are compared with results of hexagonal-based cellular models of colony growth. Lateral budding of coral colonies is simulated by an algorithm wherein the probability of branching increases with increasing lateral extension according to the relationship P=1-[1/(x-1)n], where x is the number of consecutive serial corallites and n is a power law scaling constant.