Stephen F. Greb and Paul E. Potter
Figure 1. Stratigraphy of the Fort Payne Formation in south-central Kentucky.
Formations are colored to highlight mapped units (modified from Greb and others, 2008).
The Fort Payne Formation is a gray, silica-rich dolostone to dolosiltstone (dolomitic siltstone), with lesser amounts of limestone, chert, sandstone, and shale. It contains interesting skeletal buildups ("mounds" in Figure 1) composed of green shale and flanking carbonates, which are similar in many respects to Waulsortian mounds. The Fort Payne is Early to Middle Mississippian (early Kinderhookian to late Osagean) in age, but the lower 3 ft of the unit spans the entire Lower Mississippian. In south-central Kentucky, the Fort Payne Formation conformably overlies the Late Devonian (Chautaquan) Chattanooga Shale, and is conformably overlain by the late Middle Mississippian (early Meramecian) Salem-Warsaw Limestone. Laterally, the Fort Payne Formation has an interesting geometric and temporal relationship with the Early to Middle Mississippian (early Kinderhookian to late Osagean) Borden Formation (Fig. 1), described below. Sequence stratigraphic considerations of this relationship are discussed in Khetani and Read (2002) and Krause and Meyer (2004).