|
Purgatoire Formation
The Purgatoire Formation is an abandoned (1987) Cretaceous period geologic formation classification. The classification was used in Colorado, New Mexico, and Oklahoma, with mentions in older geologic literature in neighboring states.Griggs and Read, 1959. Units previously classified as members of the abandoned formation, including Lytle, Mesa Rica, Pajarito, Romeroville, and Glencairn, have been generally elevated to formation rank. Particularly, significant divisions of the Purgatoire classification, Lytle and Glencairn, were realized as having characteristics of formations in their own right as well as representing the greatest disconformity in the Lower Cretaceous sediments of the Western Interior Seaway. Rather than including these promoted formations in an elevated Purgatoire Group, the Mesa Rica, Pajarito, and Romeroville were placed in a definition of the Dakota Group local to the Dry Cimarron. See also * List of fossiliferous stratigraphic units in Colorado * Pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theiophytalia
''Theiophytalia'' is a genus of herbivorous iguanodontian dinosaur from the lower Cretaceous period (Aptian-Albian stage, about 112 million years ago) of Colorado, USA. It contains a single species, ''T. kerri''. Description Detailed comparisons by Brill and Carpenter (2006) also showed that the skull differed in a number of key features from that of ''Camptosaurus'', namely: a longer, heavier, and more rugose snout; a wider dorsal process on the maxilla; a proportionally smaller antorbital fenestra; and stouter quadrate, with a bulbous articulation for the lower jaw. Compare the skull image with that of ''Camptosaurus''. Therefore, they put it into its own genus and species. Discovery In 1878, a student of Colorado College named James Kerr found a partial Ornithopod skull at Garden of the Gods Park in El Paso County, Colorado. The skull, YPM 1887, was referred by O.C. Marsh (affirmed by Gilmore, 1909), to whom the skull was given in 1886, as that of ''Camptosaurus amplus'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glencairn Formation
The Glencairn Formation is a geologic formation found in Colorado and New Mexico. It preserves fossils characteristic of the Albian Age of the Cretaceous Period. Description The Glencairn Formation consists of dark gray shale and buff sandstone and siltstone. It disconformably overlies the Lytle Formation, underlies the Dakota Group, and varies in thickness from . The formation is present from central Colorado to the valley of the Dry Cimarron in northeastern New Mexico. The formation locally contains gypsum veins and gypsum-filled desiccation cracks. The exposures at the valley of the Dry Cimarron include a basal sandstone bed, the Long Canyon Sandstone Bed, that is up to thick, is heavily bioturbated, and contains an abundant late Albian invertebrate fossil fauna. This is interpreted as infilling of a drainage system preceding the Kiowa-Skull Creek transgression. It is likely the lateral equivalent of the Tucumcari Shale. Fossils The lower beds of the formation are heavi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Fossiliferous Stratigraphic Units In Colorado
This article contains a list of fossil-bearing stratigraphic units in the state of Colorado, U.S. Sites See also * Paleontology in Colorado References * {{DEFAULTSORT:Fossiliferous stratigraphic units in Colorado Colorado Stratigraphic units A stratigraphic unit is a volume of Rock (geology), rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrology, petrographic, lithology, lithologic or paleontology, p ... Stratigraphy of Colorado Colorado geography-related lists United States geology-related lists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cimarron River (Arkansas River Tributary)
The Cimarron River ( ; iow, Ñíxgu, script=Latn or , meaning 'Salt River'; chy, Hotóao'hé'e) extends across New Mexico, Oklahoma, Colorado, and Kansas. The headwaters flow from Johnson Mesa west of Folsom in northeastern New Mexico. Much of the river's length lies in Oklahoma, where it either borders or passes through eleven counties. There are no major cities along its route. The river enters the Oklahoma Panhandle near Kenton, Oklahoma, crosses the southeastern corner of Colorado into Kansas, reenters the Oklahoma Panhandle, reenters Kansas, and finally returns to Oklahoma where it joins the Arkansas River at Keystone Reservoir west of Tulsa, Oklahoma, its only impoundment. The Cimarron drains a basin that encompasses about .Larry O'Dell, " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dakota Group
The Dakota is a sedimentary geologic unit name of formation and group rank in Midwestern North America. The Dakota units are generally composed of sandstones, mudstones, clays, and shales deposited in the Mid-Cretaceous opening of the Western Interior Seaway.Monroe, James S. and Wicander, Reed (1997) ''The Changing Earth: Exploring Geology and Evolution'' (2nd edition) Wadsworth Publishing Company, Belmont, California, page 610, The usage of the name Dakota for this particular Albian-Cenomanian strata is exceptionally widespread; from British Columbia and Alberta to Montana and Wisconsin to Colorado and Kansas to Utah and Arizona. It is famous for producing massive colorful rock formations in the Rocky Mountains and the Great Plains of the United States, and for preserving both dinosaur footprints and early deciduous tree leaves. Owing to extensive weathering of older rocks during the Jurassic and Triassic, the Dakota strata lie unconformably atop many different formations rangin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Interior Seaway
The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, and the Western Interior Sea) was a large inland sea that split the continent of North America into two landmasses. The ancient sea, which existed from the early Late Cretaceous (100 million years ago) to the earliest Paleocene (66 Ma), connected the Gulf of Mexico, through the United States and Canada, to the Arctic Ocean. The two land masses it created were Laramidia to the west and Appalachia to the east. At its largest extent, it was deep, wide and over long. Origin and geology By Late-Cretaceous times, Eurasia and the Americas had separated along the south Atlantic, and subduction on the west coast of the Americas had commenced, resulting in the Laramide orogeny, the early phase of growth of the modern Rocky Mountains. The Western Interior Seaway may be seen as a downwarping of the continental crust ahead of the growing Laramide/Rockies mountain chain. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unconformity
An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger layer, but the term is used to describe any break in the sedimentary geologic record. The significance of angular unconformity (see below) was shown by James Hutton, who found examples of Hutton's Unconformity at Jedburgh in 1787 and at Siccar Point in 1788. The rocks above an unconformity are younger than the rocks beneath (unless the sequence has been overturned). An unconformity represents time during which no sediments were preserved in a region or were subsequently eroded before the next deposition. The local record for that time interval is missing and geologists must use other clues to discover that part of the geologic history of that area. The interval of geologic time not represented is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Romeroville Sandstone
The Romeroville Sandstone is a geologic formation in northeastern New Mexico. It likely was deposited in the Cenomanian Age of the Cretaceous Period. Description The formation consists of yellow-gray quartz sandstone with minor siltstone. The sandstone is planar crossbedded and bioturbated and locally pebbly. It overlies the Pajarito Formation and is in turn overlain by the Graneros Shale. Maximum thickness is . The formation is interpreted as the onset of a marine transgression of the Greenhorn cycle 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 .... History of investigation The formation was first named by Kues and Lucas in 1987 for previously undivided Dakota Group beds at the Romeroville Gap. Kues and Lucas also identified it at Clayton Lake and in the valley of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pajarito Formation
The Pajarito Formation is a geologic formation in eastern New Mexico and west Texas. It preserves fossils dating back to the Albian Age of the Cretaceous Period. Description In Quay County, New Mexico, where the unit was first described, it consists of poorly cemented brown sandstone and gray shale and is thick. It overlies the Mesa Rica Formation and underlies the Graneros Shale, and is assigned to the Purgatoire Group. Further north, in the valley of the Dry Cimarron, the formation consists of medium gray shale and is thick. The formation was deposited in a shallow marine. or delta plain environment. This marked the onset of the Greenhorn marine cycle in northeastern New Mexico. Fossils The formation contains abundant fossil remains of the oyster '' Ostrea quadriplicata'', a fossil of early Cretaceous age. Dinosaur trackways are preserved in the sandstone and silty sandstone horizons of the formation, which is part of the "dinosaur freeway" megatracksite of New Mexic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesa Rica Sandstone
The Mesa Rica Sandstone is a geologic formation in Oklahoma and New Mexico. It preserves fossils dating back to the Cretaceous period. Description The Mesa Rica Sandstone consists of crossbedded white to buff sandstone. The sandstone is massive and medium- to coarse-grained. It is a very mature sandstone, consisting of almost pure quartz and kaolin, which may reflect its provenance as reworked sediments of the Morrison Formation, or may be due to a slow rate of deposition that permitted meteoric water (water originating as rain or snow) to circulate through the sediments for an unusually long time. In some locations, there is minor quartz-pebble conglomerate at the base of the formation, which lies on the Tucumcari Shale or Glencairn Formation. It is overlain by the Pajarito Formation and has a thickness of up to . The formation was laid down in a low- accommodation deltaic environment. Fossils Dinosaur remains diagnostic to the genus level are among the fossils that h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lytle Formation
The Lytle Formation or Lytle Sandstone is a geologic formation found in Wyoming, Colorado, and New Mexico. Description The Lytle Formation consists of white to light gray gravels and conglomerates. It is variable in thickness but is about at the type location. It is separated from the underlying Morrison Formation by a significant regional unconformity. It is overlain by the South Platte Formation or the Glencairn Formation. The formation is likely an early Cretaceous geologic unit, with its northern exposure running north and south within the Front Range foothills and the Dakota Hogback in northern Colorado and southern Wyoming where it is assigned formation rank within the Dakota Group. In south-central Colorado, the Lytle is an unassigned formation. The formation is also mapped in the valley of the Dry Cimarron in northeastern New Mexico, where it forms a prominent band in the lower parts of the cliffs. The Lytle was the last (youngest) non-marine unit to form in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation (stratigraphy)
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
