Elko Formation | |
---|---|
Stratigraphic range: Mid Eocene (Uintan)-Mid Miocene ~ | |
Type | Formation |
Sub-units | Elko Shale |
Lithology | |
Primary | Shale |
Other | Limestone |
Location | |
Coordinates | 40°48′N115°48′W / 40.8°N 115.8°W |
Approximate paleocoordinates | 41°30′N112°54′W / 41.5°N 112.9°W |
Region | Nevada |
Country | United States |
Type section | |
Named for | Elko County |
The Elko Formation, also known as Elko Shale(s), is an oil shale geologic formation in Elko County, northern Nevada, United States. The deltaic and lacustrine shales and limestones preserve fossils dating back to the Middle Eocene of the Paleogene to Middle Miocene of the Neogene period. The frog genus Elkobatrachus and ant species Pseudocamponotus elkoanus were named after the formation.
The formation ranges in age from the Middle Eocene (Uintan), with the underlying lower member dated at 46.1 ± 0.1 Ma and the upper member of the Eocene section dated at 38.9 ± 0.3 Ma. [1]
A younger section is dated to the Late Eocene to Early Oligocene (37.2 to 28.4 Ma) [2] and the Elko Shale member is dated to the Middle Miocene (16.0 to 11.6 Ma). [3]
The following fossils were reported from the formation: [1] [2] [3]
The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes in three basins along the present-day Green River in Colorado, Wyoming, and Utah. The sediments are deposited in very fine layers, a dark layer during the growing season and a light-hue inorganic layer in the dry season. Each pair of layers is called a varve and represents one year. The sediments of the Green River Formation present a continuous record of six million years. The mean thickness of a varve here is 0.18 mm, with a minimum thickness of 0.014 mm and maximum of 9.8 mm.
Florissantia is an extinct genus of flowering plants in the Malvaceae subfamily Sterculioideae known from western North America and far eastern Asia. Flower, fruit, and pollen compression fossils have been found in formations ranging from the Early Eocene through to the Early Oligocene periods. The type species is Florissantia speirii and three additional species are known, Florissantia ashwillii, Florissantia quilchenensis, and Florissantia sikhote-alinensis.
The Wheeler Shale is a Cambrian (c. 507 Ma) fossil locality world-famous for prolific agnostid and Elrathia kingii trilobite remains and represents a Konzentrat-Lagerstätte. Varied soft bodied organisms are locally preserved, a fauna and preservation style normally associated with the more famous Burgess Shale. As such, the Wheeler Shale also represents a Konservat-Lagerstätten.
Brachyhyops is an extinct genus of entelodont artiodactyl mammal that lived during the Eocene Epoch of western North America and southeastern Asia. The first fossil remains of Brachyhyops are recorded from the late Eocene deposits of Beaver Divide in central Wyoming and discovered by paleontology crews from the Carnegie Museum of Natural History during the early 20th century. The type species, Brachyhyops wyomingensis, is based on a single skull and was named by E.H. Colbert in 1937, but was not officially described until 1938. During the latter half of the 20th century, additional specimens from North America have been recorded from Saskatchewan and as far south as Texas, indicating that Brachyhyops had a broad distribution and was well-dispersed throughout western North America.
The Laventan age is a period of geologic time within the Middle Miocene epoch of the Neogene, used more specifically within the SALMA classification in South America. It follows the Colloncuran and precedes the Mayoan age.
The Nanjemoy Formation is a geologic formation pertaining to both the Wilcox Group and the Pamunkey Group of the eastern United States, stretching across the states of Virginia, Maryland, and District of Columbia. The formation crops out east of the Appalachians and dates back to the Paleogene period. Specifically to the Ypresian stage of the Eocene epoch, about 55 to 50 Ma or Wasatchian in the NALMA classification, defined by the contemporaneous Wasatch Formation of the Pacific US coast.
The Wasatch Formation (Tw) is an extensive highly fossiliferous geologic formation stretching across several basins in Idaho, Montana, Wyoming, Utah and western Colorado. It preserves fossils dating back to the Early Eocene period. The formation defines the Wasatchian or Lostcabinian, a period of time used within the NALMA classification, but the formation ranges in age from the Clarkforkian to Bridgerian.
The Coyote Butte Limestone (OR085) is a geologic formation in Oregon. It preserves fossils dating back to the Sakmarian to Kungurian stages of the Permian period, spanning an estimated 23 million years. The formation occurs in isolated buttes to the north; Triangulation Hill, and south; type locality and name giver Coyote Butte and Tuckers Butte, on either side of the Grindstone and Twelvemile Creeks in Crook County, Oregon.
The Coldwater Beds are a geologic formation of the Okanagan Highlands in British Columbia, Canada. They preserve fossils dating back to the Ypresian stage of the Eocene period, or Wasatchian in the NALMA classification.
Archiponera is an extinct genus of ant in the formicid subfamily Ponerinae. The genus contains a single described species, Archiponera wheeleri known from several Late Eocene fossils which were found in North America.
The Pisco Formation is a geologic formation located in Peru, on the southern coastal desert of Ica and Arequipa. The approximately 640 metres (2,100 ft) thick formation was deposited in the Pisco Basin, spanning an age from the Late Miocene up to the Early Pliocene, roughly from 9.6 to 4.5 Ma. The tuffaceous sandstones, diatomaceous siltstones, conglomerates and dolomites were deposited in a lagoonal to near-shore environment, in bays similar to other Pacific South American formations as the Bahía Inglesa and Coquimbo Formations of Chile.
Casaleia is an extinct genus of ants in the formicid subfamily Amblyoponinae described by Pagliano & Scaramozzino in 1990 from fossils found in Europe. The genus contains four species dating from the Eocene to Miocene, Casaleia eocenica, Casaleia inversa, Casaleia longiventris, Casaleia orientalis.
Pachycondyla? messeliana is an extinct species of ants in the formicid subfamily Ponerinae described by from a fossil found in Europe. P.? messeliana is one of six Lutetian Pachycondyla species.
Miocochilius is an extinct genus of small notoungulate mammals (typotheres) native to South America. The genus lived during the Middle Miocene epoch. The genus contains two described species, the type species M. anomopodus described in 1953 by Ruben Arthur Stirton and M. federicoi, described and included in the genus by Darin A. Croft.
The Onzole Formation is an Early Pliocene geologic formation in the Borbón Basin of northwestern Ecuador. The formation consists of a shallow marine sandstone member containing many fish fossils, among which megalodon, and a deep water member comprising tuffaceous shales and mudstones containing gastropods, bivalves and scaphopods.
Pseudocamponotus is an extinct, monotypic genus of ant. This genus was first described by F.M. Carpenter in 1930. The type species is Pseudocamponotus elkoanus, whose fossil was found in Nevada.
The Geste Formation is a fossiliferous geologic formation of the Puna Plateau in the western Salta Province and northern Catamarca Province of the Argentine Northwest, northwestern Argentina.
Pinus latahensis is an extinct species of conifer in the pine family Pinaceae. The species is known from fossil leaves found in the early Eocene deposits of northern Washington state, United States, and southern British Columbia, Canada.