KGS Home > Geology of Kentucky
Gray-Green Fossiliferous Shale
Gray-green, glauconitic fossiliferous shale occurs throughout the lower Fort Payne Formation and enclosed (overaid) all of the carbonate buildups (Fig. 1). Krause and Meyer (2004) called this the green (fossiliferous) shale facies and combined it with green shales in the core of the buildups. Knox and Stapor (2003) called shales above the Fort Payne buildups in Tennessee "chippy" shales. Shales above buildups are generally more gray than the core shales within the buildups, but may also have a green appearance. Weathering and wetness influence the color of both shales. Herein, the overlying shales are separated from the core shales based solely on relative position.
Figure 1. Typical appearance of gray-green fossiliferous shale facies draping (above) Fort Payne buildups.
Gray-green shales above Fort Payne buildups generally have more distinct bedding than the core shales do. Bedding within the shale drapes the underlying buildup and often exhibits slumping and deformation off of the mound flanks (Fig. 2). The capping shales may contain thin interbedded limestone (packstone and wackestone) beds, which are dominated by crinoidal debris. Capping shales have a diverse macrofauna that is common to very abundant but has a patchy distribution. Disarticulated echinoderm plates are the dominant faunal element, but brachiopods (31 genera) and bryozoans (four morphotypes) are also common (Krause and Meyer, 2004).
Figure 2. Downdip slumping of green shales above a Fort Payne buildup.
Back to Typical Facies of Fort Payne Buildups
Continue to Coarse Crinoidal Packstones and Grainstones
Back to top of Geology of the Fort Payne Formation