Fort Payne Formation
Encyclopedia
The Fort Payne Formation, or Fort Payne Chert, is a geologic formation
found in the southeastern region
of the United States
. It is a Mississippian
chert
y limestone
that overlies the Chattanooga Shale (or locally the Maury Formation) and underlies the St. Louis Limestone
(lower Tuscumbia Limestone in Alabama). To the north, it grades into the siltstone
Borden Formation
. Eugene Allen Smith named the Fort Payne Formation for outcrops at Fort Payne, Alabama
.
Geologic formation
A formation or geological formation is the fundamental unit of lithostratigraphy. A formation consists of a certain number of rock strata that have a comparable lithology, facies or other similar properties...
found in the southeastern region
Southeastern United States
The Southeastern United States, colloquially referred to as the Southeast, is the eastern portion of the Southern United States. It is one of the most populous regions in the United States of America....
of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. It is a Mississippian
Mississippian (geologic period)
The Mississippian is a subperiod in the geologic timescale or a subsystem of the geologic record. It is the earliest/lowermost of two subperiods of the Carboniferous period lasting from roughly 359 to 318 Ma...
chert
Chert
Chert is a fine-grained silica-rich microcrystalline, cryptocrystalline or microfibrous sedimentary rock that may contain small fossils. It varies greatly in color , but most often manifests as gray, brown, grayish brown and light green to rusty red; its color is an expression of trace elements...
y limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
that overlies the Chattanooga Shale (or locally the Maury Formation) and underlies the St. Louis Limestone
St. Louis Limestone
The St. Louis Limestone is a large geologic formation covering a wide area of the midwest of the United States. It is named after an exposure at St. Louis, Missouri. It consists of sedimentary limestone with scattered chert beds, including the heavily chertified Lost River Chert Bed in the Horse...
(lower Tuscumbia Limestone in Alabama). To the north, it grades into the siltstone
Siltstone
Siltstone is a sedimentary rock which has a grain size in the silt range, finer than sandstone and coarser than claystones.- Description :As its name implies, it is primarily composed of silt sized particles, defined as grains 1/16 - 1/256 mm or 4 to 8 on the Krumbein phi scale...
Borden Formation
Borden Formation
The Mississippian Borden Formation is a mapped bedrock unit in Kentucky, Indiana, Illinois, Ohio, West Virginia, and Tennessee. It has many members, which has led some geologists to consider it a group rather than a formation .-Fossils:*Corals: Cornularia sp. , Paracornularia sp...
. Eugene Allen Smith named the Fort Payne Formation for outcrops at Fort Payne, Alabama
Fort Payne, Alabama
Fort Payne is a city in DeKalb County, Alabama, United States. At the 2000 census the population was 12,938. The city is the county seat of DeKalb County. It bills itself as the "Official Sock Capital of the World."...
.