Cody Shale

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Cody Shale
Stratigraphic range: Late Cretaceous
Type Sedimentary
Sub-unitssee text
Underlies Mesaverde Formation
Overlies Frontier Formation
Thickness500-1000 m
Lithology
Primary shale
Location
RegionMontana folded belt province, Central Montana uplift, Big Horn basin, Powder River basin, Wind River basin
Country United States
ExtentWyoming, Idaho, Montana
Type section
Named for Cody, Wyoming
Named byC. T. Lupton, 1916 [1]

The Cody Shale is a Late Cretaceous geologic formation. It is mapped in Wyoming, Idaho, and Montana.

The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series. The Cretaceous is named after the white limestone known as chalk which occurs widely in northern France and is seen in the white cliffs of south-eastern England, and which dates from this time.

Wyoming U.S. state in the United States

Wyoming is a state in the mountain region of the Western United States. The state is the 10th largest by area, the least populous, and the second most sparsely populated state in the country. Wyoming is bordered on the north by Montana, on the east by South Dakota and Nebraska, on the south by Colorado, on the southwest by Utah, and on the west by Idaho and Montana. The state population was estimated at 577,737 in 2018, which is less than 31 of the most populous U.S. cities including Denver in neighboring Colorado. Cheyenne is the state capital and the most populous city, with an estimated population of 63,624 in 2017.

Idaho U.S. state in the United States

Idaho is a state in the northwestern region of the United States. It borders the state of Montana to the east and northeast, Wyoming to the east, Nevada and Utah to the south, and Washington and Oregon to the west. To the north, it shares a small portion of the Canadian border with the province of British Columbia. With a population of approximately 1.7 million and an area of 83,569 square miles (216,440 km2), Idaho is the 14th largest, the 12th least populous and the 7th least densely populated of the 50 U.S. states. The state's capital and largest city is Boise.

The formation is described by W.G. Pierce as follows: upper part is buff, sandy shale and thinly laminated buff sandstone; lower part is dark gray, thin-bedded marine shale. [2]

The formation is divided into many members that vary regionally. Alphabetically: [3]

The Belle Fourche Formation or Belle Fourche Shale is a geologic unit classification in Montana, North Dakota, South Dakota, and Wyoming, formed in a stage of the Western Interior Seaway, and roughly corresponding in age with the Graneros Shale classification in states to the south and east. It preserves fossils dating back to the Cretaceous period.

Carlile Formation

The Carlile Formation or Carlile Shale is a Turonian age Upper/Late Cretaceous series shale geologic formation in the central-western United States, including in the Great Plains region of Colorado, Kansas, Nebraska, New Mexico, North Dakota, South Dakota, and Wyoming.

Greenhorn Limestone

The Greenhorn Limestone or Greenhorn Formation is a geologic formation in the Great Plains Region of the United States. It preserves fossils dating back to the Cenomanian and Turonian of the Late Cretaceous period.

Certain members rise to formation rank in other areas; for example, the Greenhorn is classified as a formation in a number of states, particularly in Colorado and Kansas.

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Lance Formation

The Lance (Creek) Formation is a division of Late Cretaceous rocks in the western United States. Named after Lance Creek, Wyoming, the microvertebrate fossils and dinosaurs represent important components of the latest Mesozoic vertebrate faunas. The Lance Formation is Late Maastrichtian in age, and shares much fauna with the Hell Creek Formation of Montana and North Dakota, the Frenchman Formation of southwest Saskatchewan, and the lower part of the Scollard Formation of Alberta.

San Juan Basin geologic structural basin

The San Juan Basin is a geologic structural basin located near the Four Corners region of the Southwestern United States. The basin covers 7,500 square miles and resides in northwestern New Mexico, southwestern Colorado, and parts of Utah and Arizona. Specifically, the basin occupies space in the San Juan, Rio Arriba, Sandoval, and McKinley counties in New Mexico, and La Plata and Archuleta counties in Colorado. The basin extends roughly 100 miles N-S and 90 miles E-W.

Shawangunk Formation

The Silurian Shawangunk Formation is a mapped bedrock unit in eastern Pennsylvania, New Jersey, and New York. It is named for the Shawangunk Ridge for which it is the dominant rock type. The division of the Shawangunk between the Tuscarora Formation and Clinton Group has not been conclusively determined. The shift of nomenclature currently has the divide between Hawk Mountain and Lehigh Gap.

Bloomsburg Formation

The Silurian Bloomsburg Formation is a mapped bedrock unit in Pennsylvania, New Jersey, New York and Maryland. It is named for the town of Bloomsburg, Pennsylvania in which it was first described. The Bloomsburg marked the first occurrence of red sedimentary rocks in the Appalachian Basin.

Wills Creek Formation Bedrock unit in the Eastern United States

Wills Creek Formation is a mapped Silurian bedrock unit in Pennsylvania, Maryland, Virginia, and West Virginia.

Hamilton Group

The Devonian Hamilton Group is a mapped bedrock unit in the United States. The unit is present in New York, Pennsylvania, Maryland, Ohio and West Virginia. In Virginia, it is known as the laterally equivalent Millboro Shale. The group is named for the village of Hamilton, New York. Details of stratigraphic nomenclature for this unit as used by the U.S. Geological Survey are available on-line from the National Geologic Map Database. These rocks are the oldest strata of the Devonian gas shale sequence.

The Devonian Mahantango Formation is a mapped bedrock unit in Pennsylvania, West Virginia, and Maryland. It is named for the North branch of the Mahantango Creek in Perry and Juniata counties in Pennsylvania. It is a member of the Hamilton Group, along with the underlying the Marcellus Formation Shale. South of Tuscarora Mountain in south central Pennsylvania, the lower members of this unit were also mapped as the Montebello Formation. Details of the type section and of stratigraphic nomenclature for this unit as used by the U.S. Geological Survey are available on-line at the National Geologic Map Database.

Pottsville Formation

The Pennsylvanian Pottsville Formation is a mapped bedrock unit in Pennsylvania, western Maryland, West Virginia, Ohio, and Alabama. It is a major ridge-former in the Ridge-and-Valley Appalachians of the eastern United States. The Pottsville Formation is conspicuous at many sites along the Allegheny Front, the eastern escarpment of the Allegheny or Appalachian Plateau.

Huntley Mountain Formation

The Huntley Mountain Formation is a late Devonian and early Mississippian mapped bedrock unit in Pennsylvania, in the United States.

The Frontier Formation is a sedimentary geological formation whose strata date back to the Late Cretaceous. The formation's extents are: northwest Colorado, southeast Idaho, southern Montana, northern Utah, and western Wyoming. It occurs in many sedimentary basins and uplifted areas.

Fernie Formation

The Fernie Formation is a stratigraphic unit of Jurassic age. It is present in the western part of the Western Canada Sedimentary Basin in western Alberta and northeastern British Columbia. It takes its name from the town of Fernie, British Columbia, and was first defined by W.W. Leach in 1914.

Elk Basin

Elk Basin is a valley on the border of Montana and Wyoming in the United States. It is an active oil field with hundreds of derricks operating in it. Geologically, it is a breached anticline formed by a deep subsurface thrust fault. Most of the rocks at the surface are Cretaceous in age, including the Lance Formation, Meeteetse Formation, Mesaverde Formation, Cody Shale, and Frontier Formation.

The Meeteetse Formation is a Late Cretaceous geologic formation occurring in Wyoming.

Mesaverde Formation

The Mesaverde Formation is a Late Cretaceous geologic formation found in areas of Colorado, New Mexico, Utah, and Wyoming, in the Western United States.

<i>Collignoniceras</i> genus of molluscs (fossil)

Collignociceras is a strongly ribbed and tuberculate, evolute ammonite from the Turonian of the western U.S. and Europe belonging to the ammonitid family Collignoniceratidae. The genus is named after the French paleontologist Maurice Collignon. The type is Collignoniceras woollgari, named by Mantell in 1822 for specimens from Sussex, England.

Hakatai Shale

The Hakatai Shale is a Mesoproterozoic rock formation that outcrops in the Grand Canyon, Coconino County, Arizona. It consists of colorful strata that exhibit colors that vary from purple to red to brilliant orange on outcrop. The colors are the result of the oxidation of iron-bearing minerals in the Hakatai Shale. It consists of lower and middle members that consist of bright-red, slope-forming, highly fractured, argillaceous mudstones and shale and an upper member composed of purple and red, cliff-forming, medium-grained sandstone. Its thickness, which apparently increases eastwards, varies form 137 to 300 m. In general, the Hakatai Shale and associated strata of the Unkar Group rocks dip northeast (10°-30°) toward normal faults that dip 60° or more toward the southwest. This can be seen at the Palisades fault in the eastern part of the main Unkar Group outcrop area. In addition, thick, prominent, and dark-colored basaltic sills and dikes cut across the purple to red to brilliant orange strata of the Hakatai Shale.

Dox Formation

The Dox Formation, also known as the Dox Sandstone, is a Mesoproterozoic rock formation that outcrops in the eastern Grand Canyon, Coconino County, Arizona. The strata of the Dox Formation, except for some more resistant sandstone beds, are relatively susceptible to erosion and weathering. The lower member of the Dox Formation consists of silty-sandstone and sandstone, and some interbedded argillaceous beds, that form stair-stepped, cliff-slope topography. The bulk of the Dox Formation typically forms rounded and sloping hill topography that occupies an unusually broad section of the canyon.

The Thermopolis Shale is a geologic formation which formed in west-central North America in the Albian age of the Late Cretaceous period. Surface outcroppings occur in central Canada, and the U.S. states of Montana and Wyoming. The rock formation was laid down over about 7 million years by sediment flowing into the Western Interior Seaway. The formation's boundaries and members are not well-defined by geologists, which has led to different definitions of the formation. Some geologists conclude the formation should not have a designation independent of the formations above and below it. A range of invertebrate and small and large vertebrate fossils and coprolites are found in the formation.

References

  1. ↑ Lupton, C.T., 1916, Oil and gas near Basin, Big Horn County, Wyoming, IN Contributions to economic geology, 1915; Part 2, Mineral fuels: U.S. Geological Survey Bulletin, 621-L, p. L157-L190.
  2. ↑ Pierce, W.G., 1997, Geologic map of the Cody 1 degree x 2 degrees quadrangle, northwestern Wyoming: U.S. Geological Survey, Miscellaneous Geologic Investigations Map I-2500, scale 1:250000.
  3. ↑ "Geologic Unit: Cody". National Geologic Database. Geolex — Unit Summary. United States Geological Survey. Retrieved 2018-06-29.


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