Golden Valley Formation | |
---|---|
Stratigraphic range: Late Paleocene-Early Eocene (Clarkforkian-Wasatchian) ~ | |
Type | Geological formation |
Sub-units | Bear Den & Camels Butte Members |
Underlies | White River Group |
Overlies | Sentinel Butte Formation |
Thickness | up to 122 metres (400 ft) [1] |
Lithology | |
Primary | Claystone, mudstone, siltstone, sandstone |
Other | Lignite, conglomerate |
Location | |
Coordinates | 48°30′N102°42′W / 48.5°N 102.7°W |
Approximate paleocoordinates | 52°54′N82°12′W / 52.9°N 82.2°W |
Region | North Dakota |
Country | United States |
Extent | Williston Basin |
Type section | |
Named for | Golden Valley, North Dakota |
Named by | Benson & Laird [2] |
Year defined | 1947 |
The Golden Valley Formation is a stratigraphic unit of Late Paleocene to Early Eocene age in the Williston Basin of North Dakota. [3] It is present in western North Dakota and was named for the city of Golden Valley by W.E. Benson and W.M. Laird in 1947. [2] It preserves significant assemblages of fossil plants [3] and vertebrates, [4] as well as mollusk and insect fossils. [3] [4]
The Golden Valley Formation was named in 1947. [2]
Between 1958–61, a large field expedition conducted by the Yale Peabody Museum recovered a plethora of crocodilian remains from the White Butte and Turtle Valley sites (collectively referred to as the South Heart Locality) within the Golden Valley Formation. [5] [6]
The Golden Valley Formation is present as a series of outliers in western North Dakota. [7] It is underlain by the Sentinel Butte Formation and unconformably overlain by the White River Group. [1] It reaches thicknesses of up to 122 metres (400 ft) and is subdivided into two members: the Bear Den Member (lower) and the Camels Butte Member (upper). [1]
The base of the Bear Den Member consists of kaolinitic claystone, mudstone and sandstone that weather to white, light grey, orange, and purple. [1] These are overlain by grey or brownish carbonaceous sediments and, in some areas, a bed of lignite (the Alamo Bluff lignite). [3] In places the sequence is capped by a siliceous bed (the Taylor bed [3] ) that represents a weathering surface or paleosol. [1] The Bear Den Member reaches a maximum thickness of about 15 metres (50 ft). [1]
The Camels Butte Member consists of montmorillonitic [3] and micaceous claystone, siltstone, lignite, poorly cemented sandstone and conglomerate. [1] [3] The upper part includes a massive fluvial sandstone that caps many of the major buttes in southwestern North Dakota. [1] The Camels Butte Member reaches a maximum thickness of about 107 metres (350 ft). [1]
The Golden Valley Formation was deposited in a broad swampy lowland crossed by fluvial channels. [3] Deposition occurred during late Paleocene (Clarkforkian) to early Eocene (Wasatchian) time, [3] a period that spans the Paleocene-Eocene Thermal Maximum. [8]
Plant fossils collected from throughout the formation include floating and rooted aquatic plants such as Salvinia , Nelumbo and Isoetes , and lowland forest plants such as the ferns Onoclea and Osmunda , the conifers Glyptostrobus and Metasequoia , and the dicots Platanus and Cercidiphyllum . [3]
The vertebrate fossils have come primarily from the upper, early Eocene Camels Butte Member. They include the remains of mammals such as Coryphodon , Hyracotherium , Homogalax , Sinopa , Didymictis , Hyopsodus , Paramys and others; there are also remains of fish, amphibians, and reptiles such as Trionyx , Peltosaurus , and four genera of crocodilians. [3] [4]
Invertebrate fossils include shells of freshwater mollusks such as Viviparus , Unio , Hydrobia , and Planorbis , and the wing casing of a crabid beetle. [3] [4]
The Wannagan Creek site is a fossil site found just west of the South Unit of Theodore Roosevelt National Park of North Dakota, US. The site is Paleocene in age, approximately 60 million years old. Paleontologists of the Science Museum of Minnesota have studied the site for nearly thirty years. The site is thought to represent a paleoenviroment of subtropical swampy lowland and forests. Preservation is excellent for both the flora and fauna of the site. Trace fossils of crocodilians and other vertebrates have also been discovered.
The North Horn Formation is a widespread non-marine sedimentary unit with extensive outcrops exposed in central and eastern Utah. The formation locally exceeds 3,600 feet (1,100 m) in thickness and is characterized by fluvial, lacustrine, and floodplain dominated systems, representing a terrestrial, high energy, depositional environment. The sediments date from Late Cretaceous (Maastrichtian) to early Paleocene in age and include the K-Pg extinction event boundary; however, this boundary is extremely difficult to locate and there is no strong stratigraphic evidence available that indicates a specific marker bed such as an iridium rich clay layer. Thus far, the only visible evidence is represented in the form of faunal turnover from dinosaur to mammal-dominated fossil assemblages. Taxa from the Cretaceous part of the formation include squamates, testudines, choristoderes, crocodyliforms, sharks, bony fishes, amphibians, mammals, dinosaurs, eggshell fragments, trace fossils, mollusks, plant macrofossils, such as wood fragments, and palynomorphs.
The McRae Group is a geological group exposed in southern New Mexico whose strata, including layers of the Hall Lake Formation and Jose Creek Formation, date to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from this unit.
The Denver Formation is a geological formation that is present within the central part of the Denver Basin that underlies the Denver, Colorado, area. It ranges in age from latest Cretaceous (Maastrichtian) to early Paleocene, and includes sediments that were deposited before, during and after the Cretaceous-Paleogene boundary event.
The Nacimiento Formation is a sedimentary rock formation found in the San Juan Basin of western New Mexico. It has an age of 61 to 65.7 million years, corresponding to the early and middle Paleocene. The formation has yielded an abundance of fossils from shortly after the Cretaceous-Paleogene extinction event that provide clues to the recovery and diversification of mammals following the extinction event.
Navajosuchus is an extinct genus of alligatorine crocodylian. Its fossils have been found in the Paleocene-age Nacimiento Formation of the San Juan Basin, New Mexico. It was named in 1942 by Charles C. Mook, and the original type species was N. novomexicanus. N. novomexicanus was based on AMNH 5186, a partial skull collected in 1913. Later research showed that Navajosuchus novomexicanus was the same as the earlier-named Allognathosuchus mooki. However, A. mooki does not belong to the genus Allognathosuchus, and so the name of the crocodilian becomes Navajosuchus mooki. Under whichever name is used, this animal would have been a generalized predator of the Nacimiento floodplains. It was the most common Nacimiento Formation crocodilian, found in both the Puercan and Torrejonian faunal assemblages.
The Ravenscrag Formation is a stratigraphic unit of early Paleocene age in the Western Canada Sedimentary Basin. It was named for the settlement of Ravenscrag, Saskatchewan, and was first described from outcrops at Ravenscrag Butte near the Frenchman River by N.B. Davis in 1918.
Peltandra primaeva is an extinct species of monocot in the family Araceae known from a Ypresian age Eocene fossil found in western North Dakota, USA.
Nelumbo aureavallis is an extinct species of flowering plants in the lotus family known from Ypresian age Eocene fossils found in western North Dakota, USA.
The geology of the Isle of Wight is dominated by sedimentary rocks of Cretaceous and Paleogene age. This sequence was affected by the late stages of the Alpine Orogeny, forming the Isle of Wight monocline, the cause of the steeply-dipping outcrops of the Chalk Group and overlying Paleogene strata seen at The Needles, Alum Bay and Whitecliff Bay.
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 Blairmore Group, originally named the Blairmore Formation, is a geologic unit of Early Cretaceous age in the Western Canada Sedimentary Basin that is present in southwestern Alberta and southeastern British Columbia. It is subdivided into four formations: Cadomin Formation, Gladstone, Beaver Mines and Ma Butte, all of which are defined by type sections, most of which contain plant fossils. In some areas the Blairmore contains significant reservoirs of natural gas.
The Whitemud Formation is a geologic formation of Late Cretaceous (Maastrichtian) age in the Western Canada Sedimentary Basin. it is present through the plains of southern Saskatchewan, southeastern Alberta and south-central Alberta. Named by N.B. Davis in 1918, the formation is characterized by white kaolinitic clay and is a source of high-quality refractory clay. The type locality has been designated as Dempster's clay pit northwest of Eastend, Saskatchewan.
The Bogotá Formation (Spanish: Formación Bogotá, E1-2b, Tpb, Pgb) is a geological formation of the Eastern Hills and Bogotá savanna on the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The predominantly shale and siltstone formation, with sandstone beds intercalated, dates to the Paleogene period; Upper Paleocene to Lower Eocene epochs, with an age range of 61.66 to 52.5 Ma, spanning the Paleocene–Eocene Thermal Maximum. The thickness of the Bogotá Formation ranges from 169 metres (554 ft) near Tunja to 1,415 metres (4,642 ft) near Bogotá. Fossils of the ungulate Etayoa bacatensis have been found in the Bogotá Formation, as well as numerous reptiles, unnamed as of 2017.
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The geology of Wyoming includes some of the oldest Archean rocks in North America, overlain by thick marine and terrestrial sediments formed during the Paleozoic, Mesozoic and Cenozoic, including oil, gas and coal deposits. Throughout its geologic history, Wyoming has been uplifted several times during the formation of the Rocky Mountains, which produced complicated faulting that traps hydrocarbons.
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The geology of Afghanistan includes nearly one billion year old rocks from the Precambrian. The region experienced widespread marine transgressions and deposition during the Paleozoic and Mesozoic, that continued into the Cenozoic with the uplift of the Hindu Kush mountains.
Ahdeskatanka is an extinct genus of alligator from the Early Eocene Golden Valley Formation of North Dakota, USA. Ahdeskatanka had a short, rounded snout with globular teeth that are well-suited for crushing hard-shelled prey, though its exact ecology is not known. Ahdeskatanka inhabited the vast wetlands that covered much of western North Dakota during the Early Eocene Climatic Optimum, an environment it shared with at least three other crocodilians. These include the large caiman Chrysochampsa and at least two unnamed forms, one a large crocodyloid and one more similar to Ahdeskatanka. Phylogenetic analysis suggests that it was an early diverging member of the Alligatorinae, possibly related to Allognathosuchus, though its position is not very stable. Only a single species, Ahdeskatanka russlanddeutsche, is placed in this genus.
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