| Red Eagle Formation | |
|---|---|
| Stratigraphic range: Carboniferous-Permian boundary [1] | |
| Type | Formation |
| Unit of | Council Grove Group |
| Sub-units | In Kansas and Nebraska: *Howe Limestone *Bennett Shale *Glenrock Limestone |
| Lithology | |
| Primary | Limestone |
| Other | Shale |
| Location | |
| Coordinates | 36°52′21″N96°33′56″W / 36.87250°N 96.56556°W |
| Region | Midcontinent (Oklahoma, Kansas, Nebraska) |
| Country | United States |
| Type section | |
| Named for | Red Eagle School, southwest of Foraker, Oklahoma [2] |
| Named by | K.C. Heald |
| Year defined | 1916 |
The Red Eagle Formation (or Red Eagle Limestone) is a geologic formation ranging from Oklahoma, through Kansas, into southeast Nebraska of the United States. [2] Its members define the Carboniferous-Permian boundary in Kansas. [1]
In the Oklahoma type location, the Red Eagle is a single limestone unit, not further defined into members. However, from the far southeast Nebraska type section into northern Kansas, the Red Eagle Formation consists of three members, each with distinctive lithologies. In Nebraska and northern Kansas in particular, the formation stands out on riverside bluffs and road cuts as two blocky, light-colored limestones sandwiching a dark layer of shale. [2]
Named from exposures south of Howe, Nebraska, the Howe Limestone member is a grey limestone, 4-5 feet thick, that weathers to buff or slightly yellow. The limestone exhibits brachiopods, baculites, and larger bivalve mollusks. [3] The environment was an open, but very shallow sea with very little in the way of terrogenous sediments. As such, the topmost bed is particularly notable for algae beds and melon-sized stromatolites.
Named from exposures along the Little Nemaha River and its branches south of Bennet, Nebraska, the Bennett Shale member is a dark, carbonaceous shale, 2.5 to 15 feet thick. [4] This very dark shale shows contrasting light-colored, circular, thin-shelled Orbiculoidea, roughly 1cm (1/3") in diameter. However, south of Interstate 70 in Kansas, the member becomes increasing limestone to the point that within Oklahoma, the bed is completely limestone and the Red Eagle unit undivided by any significant shale bed.
The Bennett is the youngest Permian rock unit in Kansas.
Named from exposures high in valley sides just northwest of Glenrock, Nebraska, the Glenrock Limestone member is lighter grey. [5] It is a hard limestone; fresh fractures sparkle in full sunlight from tiny calcite crystals.
The Glenrock is the oldest Carboniferous rock unit in Kansas.
The Kiowa Formation or Kiowa Shale is a Cretaceous geologic formation in Kansas, diminishing to member status in Colorado and Oklahoma. In Colorado, the Kiowa Shale was classified as a member of the now abandoned Purgatoire Formation. In the vicinity of Longford, Kansas, the local Longford member comprises thinly bedded siltstone, clay, polished gravel, lignite, and sandstone suggests a river and estuary environment.
Kansas City is a Late Carboniferous geologic group and formation having various significant alternating beds of limestone and shale known for forming high bluffs in Missouri, Kansas, and neighboring states. This formation was named for the bluffs within Kansas City, Missouri. Primary group outcrops are in northwest Missouri. This group has been a historic oil producing unit within the state of Kansas.
The Oread Limestone is a geologic unit of formation rank within the Shawnee Group throughout much of its extent. It is exposed in Kansas, Nebraska, Missouri, Oklahoma, and Iowa. The type locality is Mount Oread within Lawrence, Kansas. It preserves fossils of the Carboniferous period. Although it has significant shale members, its limestone members are resistant and form escarpments and ridges. Limestone from the unit is a historic building material in Kansas, particularly in the early buildings of the University of Kansas; standing examples include Spooner Hall and Dyche Hall.
The Stanton Formation is a geologic formation of limestone in Iowa, Nebraska, Missouri and Kansas. It preserves fossils dating back to the Carboniferous period. It is in the Upper Pennsylvanian series, forming the top of the Lansing Group.
The Graneros Shale is a geologic formation in the United States identified in the Great Plains as well as New Mexico that dates to the Cenomanian Age of the Cretaceous Period. It is defined as the finely sandy argillaceous or clayey near-shore/marginal-marine shale that lies above the older, non-marine Dakota sand and mud, but below the younger, chalky open-marine shale of the Greenhorn. This definition was made in Colorado by G. K. Gilbert and has been adopted in other states that use Gilbert's division of the Benton's shales into Carlile, Greenhorn, and Graneros. These states include Kansas, Texas, Oklahoma, Nebraska, and New Mexico as well as corners of Minnesota and Iowa. North Dakota, South Dakota, Wyoming, and Montana have somewhat different usages — in particular, north and west of the Black Hills, the same rock and fossil layer is named Belle Fourche Shale.
The Greenhorn Limestone or Greenhorn Formation is a geologic formation in the Great Plains Region of the United States, dating to the Cenomanian and Turonian ages of the Late Cretaceous period. The formation gives its name to the Greenhorn cycle of the Western Interior Seaway.
The Janesville Shale or Janesville Formation is a geologic formation in Kansas, Oklahoma, and Nebraska dating to the late Carboniferous period.
The Beattie Formation, or Beattie Limestone, is a geologic formation in east-central Kansas, northeast-central Oklahoma, and southeastern Nebraska in the Midwestern United States. It preserves fossils dating to the Permian period.
The Council Grove Group is a geologic group in Kansas, Oklahoma, and Nebraska as well as subsurface Colorado. It preserves fossils dating to the Carboniferous-Permian boundary. This group forms the foundations and lower ranges of the Flint Hills of Kansas, underlying the Chase Group that forms the highest ridges of the Flint Hills.
The Americus Limestone is a member of the Foraker Limestone Formation in eastern Kansas, where it is quarried as a distinctive ornamental stone. In outcrop, it is typically recognized as two relatively thin but persistent beds of hard limestone separated by shale that forms the lowest prominent bench of the many benches of the Flint Hills. The recognizable facie of the member in excavated or eroded exposures is two thin limestone beds separated a bed of shale and adjacent shales above and below having a particular gray or bluish color darker than higher limestones. A third, lower, highly variable algal limestone is often present and included as the base of the member. The unit is not particularly massive, the limestone pair totaling 3 to 4 feet in places, more in other locations but less to the North, and up to nearly to 9 feet at the type location of Americus, Kansas. The addition of the lower algal limestone as a base for the unit increases the thickness to over 18 feet. Initially thought to be the lowest of the Permian rock of Kansas and as such classified as the lowest unit of the Council Grove Group, the unit is now dated within the uppermost Late Carboniferous.
The Wellington Formation is an Early Permian geologic formation in Kansas and Oklahoma. The formation's Hutchinson Salt Member is more recognized by the community than the formation itself, and the salt is still mined in central Kansas. The Wellington provides a rich record of Permian insects and its beddings provide evidence for reconstruction of tropical paleoclimates of the Icehouse Permian with the ability in cases to measure the passage of seasons. Tens of thousands of insect fossil recovered from the Wellington shales are kept in major collections at the Harvard Museum of Comparative Zoology and Yale Peabody Museum of Natural History.
The Speiser Shale or Speiser Formation is a geologic formation in Kansas, Oklahoma, and Nebraska dating to the early Permian period.
The Eskridge Shale or Eskridge Formation is an Early Permian geologic formation in Kansas. Its outcrop runs north–south through Kansas, extending into Oklahoma and Nebraska. While named a shale, it features extensive, spectacular red and green stacked palosol mudstones, these mudstones showing prominent vertical tubular carbonate concretions, possibly from roots or vertebrate burrows.
The Funston Limestone is a Permian geologic formation in Kansas having various significant beds of limestone with some shale. This formation was named for Camp Funston, Riley County, Kansas, in 1931 by Condra, G.E., and Upp, J.E.. Adjoining the old camp, some of the oldest buildings in Ogden, Kansas, are built with near-white Funston Limestone.
The Foraker Formation is a geologic formation in Nebraska, Kansas, and Oklahoma. It preserves fossils dating to the Carboniferous period.
The Johnson Formation is a thick geologic formation of soft shale with thin, resistant beds of chalkier mudstone and limestone in Nebraska, Kansas, and Oklahoma rarely exposed outside of road cuts. It preserves fossils dating back to the late-Carboniferous period.
The Grenola Formation is an early Permian geologic formation (Wolfcampian) with its exposure running north and south through Kansas and extending into Nebraska and Oklahoma, notably having the Neva Limestone member, which is a terrace-forming aquifer and historic Flint Hills building stone source secondary to the Cottonwood Limestone.
Cottonwood Limestone, or simply the Cottonwood, is a stratigraphic unit and a historic stone resource in east-central Kansas, northeast-central Oklahoma, and southeastern Nebraska in the Midwestern United States. It is the lowest member of the Beattie Limestone formation and commonly outcrops within the deep valleys and on top of the scenic residual ridges of the Flint Hills.
The Florena Shale is a stratigraphic unit in east-central Kansas, northeast-central Oklahoma, and southeastern Nebraska in the Midwestern United States. It preserves fossils dating to the Permian period.
The Roca Formation is an early Permian geologic formation (Wolfcampian) with its exposure running north and south through Kansas and extending into Nebraska and Oklahoma, notably comprising varicolored black, brown, gray, green, red, and blue shales, mudstones, and limestone, some of which representing Permian paleosols.
... the Carboniferous-Permian boundary in Kansas can now be confidently defined. Based [on fossil changes, the] boundary in Kansas can be placed at the base of the Bennett Shale Member of the Red Eagle Limestone.
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