EXAMINATION OF A TABULATE CORAL BIOSTROME IN THE BULL FORK FORMATION (ORDOVICIAN), BATH COUNTY, KENTUCKY

This project examines a Late Ordovician reef complex that is exposed along Interstate 64 in Bath County, Kentucky. The reef examined consists mainly of tabulate corals of the genus Tetradium. Research methods, analyses, and interpretations assisted in determining: (1) the environmental conditions under which this reef first established itself, (2) how it evolved or developed, and (3) what led to its demise.

There are five distinct lithofacies that make up this tabulate coral buildup. The section begins with a series of interbedded shales and limestones (Facies A). Lying directly over this unit is Facies B, a fossiliferous packstone that was deposited during a storm. This layer of debris is thought to have provided the hard, relatively stable surface that was initially colonized by the tabulate (Tetradium) corals making up the biostrome. The biostrome itself (Facies C) lies directly on this storm lag. The lower half is dominated by club-shaped, ramose, and hemispherical forms that have been knocked over and in many cases completely overturned. Scattered between clusters of corals and capping many of the colonies is Facies D, a grainstone to coral rudstone/floatstone. This unit was deposited as carbonate sands (grainstone) that washed in-between individual coral heads within the biostrome. The biostrome is overlain by a layer of terrigenous mud (Facies E) that buried this developing reef system. The mass of terrigenous mud that overwhelmed the system was derived from the erosion of the Taconic highlands in eastern Pennsylvanian and New York.