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.
Daphoenus is an extinct genus of amphicyonids. Daphoenus inhabited North America from the Late Eocene to the Middle Miocene, 37.2—16.0 Mya, existing for approximately 21 million years.
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Aphaenogaster mayri is an extinct species of ant in formicid subfamily Myrmicinae known from a series of Late Eocene fossils found in North America. A. mayri was one of two Aphaenogaster species described in a 1930 paper by Frank M. Carpenter.
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.
Abanico Formation is a 3 kilometres (9,800 ft) thick sedimentary formation exposed in the Andes of Central Chile. The formation has been deposited in a timespan from the Eocene to the Miocene. Abanico Formation's contact with the overlying Miocene Farellones Formation has been the subject of differing interpretations since the 1960s. A small part of the formation crops out in the Mendoza Province of western Argentina.
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.
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.
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