The Chattanooga Shale is a

geological formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock expo ...

Alabama Alabama ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South, Deep Southern regions of the United States. It borders Tennessee to the north, Georgia (U.S. state), Georgia to the east, Florida and the Gu ...

Arkansas Arkansas ( ) is a landlocked state in the West South Central region of the Southern United States. It borders Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma ...

Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...

Kansas Kansas ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the west. Kansas is named a ...

Kentucky Kentucky (, ), officially the Commonwealth of Kentucky, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Illinois, Indiana, and Ohio to the north, West Virginia to the ...

Missouri Missouri (''see #Etymology and pronunciation, pronunciation'') is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it border ...

and

Tennessee Tennessee (, ), officially the State of Tennessee, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Kentucky to the north, Virginia to the northeast, North Carolina t ...

. It preserves

conodont Conodonts, are an extinct group of marine jawless vertebrates belonging to the class Conodonta (from Ancient Greek κῶνος (''kōnos''), meaning " cone", and ὀδούς (''odoús''), meaning "tooth"). They are primarily known from their hard ...

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

dating to the

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

period. It occurs mostly as a subsurface geologic formation composed of layers of

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

. It is located in

East Tennessee East Tennessee is one of the three Grand Divisions of Tennessee defined in state law. Geographically and socioculturally distinct, it comprises approximately the eastern third of the U.S. state of Tennessee. East Tennessee consists of 33 coun ...

and also extends into southeastern Kentucky, northwestern Georgia, and northern Alabama. This part of Alabama is part of the

Black Warrior Basin The Black Warrior Basin is a geologic sedimentary basin of western Alabama and northern Mississippi in the United States. It is named for the Black Warrior River and is developed for coal and coalbed methane production, as well as for conventio ...

. The Chattanooga Shale of East Tennessee is reported to be an extension of or correlates with the

Marcellus Shale Marcellus may refer to: People * Marcellus (name) * Marcellus of Ancyra, fourth-century Christian bishop and theologian * Marcus Claudius Marcellus, Roman commander * Marcellus of Tangier * Marcellus Empiricus * Marcellus (nephew of Augustu ...

of the Appalachian region to the east. Exploratory drilling of the Chattanooga Shale in East Tennessee indicates that it contains significant amounts of

natural gas Natural gas (also fossil gas, methane gas, and gas) is a naturally occurring compound of gaseous hydrocarbons, primarily methane (95%), small amounts of higher alkanes, and traces of carbon dioxide and nitrogen, hydrogen sulfide and helium ...

. This has resulted in interest in and attempts to use

hydraulic fracturing Fracking (also known as hydraulic fracturing, fracing, hydrofracturing, or hydrofracking) is a well stimulation technique involving the fracturing of Formation (geology), formations in bedrock by a pressurized liquid. The process involves the ...

to exploit the resource. This is a particularly interesting structure, both in terms of what it represents for the region's petroleum infrastructure, and in terms of what it represented for the ancient landscapes in which it embedded.

Geological and stratigraphic overview

Chattanooga Shale belongs to the Upper Devonian (and perhaps Lower Mississippian), running from the Famennian Stage of the Devonian to the Kinderhookian Stage of the Mississippian. It is usually interpreted as dark fibrous shale made from finely fragmented silt and clay sand blown onto ancient sea beds. Shale is dark - high in organic matter - and will weather into little flat flakes, as it has small particles and layers. The Chattanooga Shale is a member of the Devonian Shale-Middle and Upper Paleozoic Total Petroleum System (TPS) stretching from New York to Tennessee that comprises six large petroleum systems. Such systems span Cambrian to Pennsylvanian intervals, and the Chattanooga Shale feeds much of the Appalachian Basin's oil and gas. Arkansas's is mostly Devonian, and the Chattanooga Shale in northeastern Oklahoma and western Kansas has perhaps a few Mississippian-age boulders at the top. Stratigraphically, the Chattanooga Shale tends to lie below the Fort Payne Chert and overlaid by limestones of various thickness and density.

Members and lithology

There are several informal members to the Chattanooga Shale ᅳ Misener Sandstone Member and lower, middle, and upper shale members. The Misener Sandstone Member in Appalachia is the formation's source. This phosphatic quartz sandstone is called the Sylamore Sandstone and is present in the Chattanooga interval also in eastern Oklahoma and northern Arkansas. These are supported by shale units, all different in composition and thickness at different locations. Within the Chattanooga Shale, especially central Kansas, there is a limestone matrix up to 12 meters thick engrained in the upper shale. A limestone directly beneath the Mississippian carbonate boundary has been a leading factor used to help identify surface exposures in the region. While there are not many fossils left in the shale – conodonts, brachiopods and uncommon microfossils of land plants, the fossils have played a major role in identifying dates and depositional conditions in the formation.

Organic richness and petroleum potential

The Chattanooga Shale is famous for its organic depth, as it is one of the largest sources of petroleum. The middle shale fraction has a high TOC level, as a result it is one of the most significant geologic units in the Appalachian Basin petroleum chains. Geochemical analyses of the shale show that the TOC level varies dramatically, and the middle part of the shale has typically the highest organics. This difference suggests that the shale has been a part of many different settings and conditions as some areas of the rock have endured more robust biotic accumulation. The Chattanooga Shale’s role in the middle and upper Paleozoic Total Petroleum System has gained a lot of studies, including natural gas studies. It acts as a reservoir for a massive number of hydrocarbons, and a good supply of that gas comes from the rocks, particularly in Kentucky, Tennessee, and West Virginia. The Chattanooga Shale’s oil reserves were appraised by USGS, which took notes on large amounts of technically recoverable gas, oil, and NGLs in most appraisals over the years (including 2006, 2008, and 2019). File:Chattanooga Shale (Upper Devonian; Burkesville West Rt. 90 roadcut, Kentucky, USA) 22 (40541682240).jpg, Chattanooga Shale in Kentucky File:Chattanooga Shale (Upper Devonian; Burkesville West Rt. 90 roadcut, Kentucky, USA) 17 (40541683280).jpg, Chattanooga Shale File:Pyrite concretion (Chattanooga Shale, Upper Devonian; Burkesville West Rt. 90 roadcut, Kentucky, USA) 1 (42300453012).jpg, Pyrite concretion in Chattanooga Shale

References

Devonian Tennessee Devonian System of North America Devonian Alabama Devonian Arkansas Devonian Georgia (U.S. state) Devonian Kansas Devonian Kentucky Devonian Missouri Shale formations of the United States Oil shale in the United States Oil-bearing shales in the United States Oil shale formations Devonian southern paleotemperate deposits Sandstone formations of the United States Geologic formations of Tennessee Geologic formations of Alabama Geologic formations of Arkansas Geologic formations of Georgia (U.S. state) Geologic formations of Kansas Geologic formations of Kentucky Geologic formations of Missouri {{Missouri-geologic-formation-stub

Geological and stratigraphic overview

Members and lithology

Organic richness and petroleum potential

See also

References