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Point Lookout Sandstone
The Point Lookout Sandstone is a Cretaceous bedrock formation occurring in New Mexico and Colorado. Description The formation consists of two informal members. The lower is a sequence of thinly bedded sandstone and shale, while the upper is a massive medium- to fine-grained cross-bedded sandstone, light gray to buff in color, that is a conspicuous cliff-forming unit. Maximum thickness is . The lower contact is placed at the first thin sandstone bed above the shale of the Mancos Shale. The formation is overlain by the Menefee Formation. The Point Lookout Sandstone was deposited in the Cretaceous Interior Seaway, as part of a regressive sequence as the seaway was receding. It is transitional between the marine environment of the underlying Mancos and the coastal plain environment of the overlying Menefee Formation. Fossils Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus. The ammo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Point Lookout (Colorado)
Point Lookout is an 8,427-foot (2,569 meter) elevation sandstone summit located in Mesa Verde National Park, in Montezuma County of southwest Colorado. This prominent landmark is situated south of the park entrance, and east-southeast of the town of Cortez, and towers 1,600 feet above the surrounding terrain of Mancos Valley. Soldiers from Fort Lewis army post used its lofty position to send heliographic signals to troops campaigning in the west. A trail climbs 2.2 miles (3.5 km) round-trip to the top and offers views of Montezuma and Mancos valleys, as well as the La Plata Mountains. This geographical feature's name was officially adopted in 1934 by the U.S. Board on Geographic Names. Geology The main entrance road to Mesa Verde National Park traverses the east flank of Point Lookout as it climbs the escarpment of the East Rim of Mesa Verde. Point Lookout is located on the Colorado Plateau, and is composed of 400-foot thick Cretaceous Point Lookout Sandstone, which is the old ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bedding (geology)
In geology, a bed is a layer of sediment, sedimentary rock, or pyroclastic material "bounded above and below by more or less well-defined bedding surfaces".Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, eds., 2005. ''Glossary of Geology'' (5th ed.). Alexandria, Virginia; American Geological Institute. p 61. Specifically in sedimentology, a bed can be defined in one of two major ways.Davies, N.S., and Shillito, A.P. 2021, ''True substrates: the exceptional resolution and unexceptional preservation of deep time snapshots on bedding surfaces.'' ''Sedimentology.'' published online 22 May 2021, doi: 10.1111/sed.12900. First, Campbell and Reineck and SinghReineck, H.E., and Singh, I.B., 1980. ''Depositional Sedimentary Environments'', (2nd ed.) Berlin, Germany: Springer-Verlag, 504 pp. use the term ''bed'' to refer to a thickness-independent layer comprising a coherent layer of sedimentary rock, sediment, or pyroclastic material bounded above and below by surfaces known as beddi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rare Earth Elements
The rare-earth elements (REE), also called the rare-earth metals or (in context) rare-earth oxides or sometimes the lanthanides (yttrium and scandium are usually included as rare earths), are a set of 17 nearly-indistinguishable lustrous silvery-white soft heavy metals. Compounds containing rare earths have diverse applications in electrical and electronic components, lasers, glass, magnetic materials, and industrial processes. Scandium and yttrium are considered rare-earth elements because they tend to occur in the same ore deposits as the lanthanides and exhibit similar chemical properties, but have different electronic and magnetic properties. These metals tarnish slowly in air at room temperature and react slowly with cold water to form hydroxides, liberating hydrogen. They react with steam to form oxides, and at elevated temperature (400°C) ignite spontaneously. These elements and their compounds have no biological function other than in several specialized enzymes, su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zirconium
Zirconium is a chemical element with the symbol Zr and atomic number 40. The name ''zirconium'' is taken from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian '' zargun'' (zircon; ''zar-gun'', "gold-like" or "as gold"). It is a lustrous, grey-white, strong transition metal that closely resembles hafnium and, to a lesser extent, titanium. Zirconium is mainly used as a refractory and opacifier, although small amounts are used as an alloying agent for its strong resistance to corrosion. Zirconium forms a variety of inorganic and organometallic compounds such as zirconium dioxide and zirconocene dichloride, respectively. Five isotopes occur naturally, four of which are stable. Zirconium compounds have no known biological role. Characteristics Zirconium is a lustrous, greyish-white, soft, ductile, malleable metal that is solid at room temperature, though it is hard and brittle at lesser purities. In powder form, zirconium is highl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in sea water, aqua regia, and chlorine. Titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791 and was named by Martin Heinrich Klaproth after the Titans of Greek mythology. The element occurs within a number of minerals, principally rutile and ilmenite, which are widely distributed in the Earth's crust and lithosphere; it is found in almost all living things, as well as bodies of water, rocks, and soils. The metal is extracted from its principal mineral ores by the Kroll and Hunter processes. The most common compound, titanium dioxide, is a popular photocatalyst and is used in the manufacture of white pigments. Other compounds include titanium tetrachloride (TiCl4), a component of smoke screens and catalysts; and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clioscaphites
''Clioscaphites'' is an extinct genus of ammonite belonging to the family Scaphitidae. Species in this genus are important index fossils of the Western Interior Seaway of the Coniacian to Santonian Ages of the Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of .... References Mesozoic animals Scaphitidae Late Cretaceous ammonites of North America {{Ammonite-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonite
Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) than they are to shelled nautiloids such as the living ''Nautilus'' species. The earliest ammonites appeared during the Devonian, with the last species vanishing during the Cretaceous–Paleogene extinction event. Ammonites are excellent index fossils, and linking the rock layer in which a particular species or genus is found to specific geologic time periods is often possible. Their fossil shells usually take the form of planispirals, although some helically spiraled and nonspiraled forms (known as heteromorphs) have been found. The name "ammonite", from which the scientific term is derived, was inspired by the spiral shape of their fossilized shells, which somewhat resemble tightly coiled rams' horns. Pliny the Elder ( 79 AD near Pomp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus comes above species and below family (taxonomy), family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is the subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya; their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds. Dinosaurs are varied from taxonomic, morphological and ecological standpoints. Birds, at over 10,700 living species, are among ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regression (geology)
A marine regression is a geological process occurring when areas of submerged seafloor are exposed above the sea level. The opposite event, marine transgression, occurs when flooding from the sea covers previously-exposed land. Evidence of marine regressions and transgressions occurs throughout the fossil record, and the fluctuations are thought to have caused or contributed to several mass extinctions, such as the Permian-Triassic extinction event (250 million years ago) and Cretaceous–Paleogene extinction event (66 Ma). During the Permian-Triassic extinction, the largest extinction event in the Earth's history, the global sea level fell 250 m (820 ft). A major regression could itself cause marine organisms in shallow seas to go extinct, but mass extinctions tend to involve both terrestrial and aquatic species, and it is harder to see how a marine regression could cause widespread extinctions of land animals. Regressions are, therefore, seen as correlates or symptoms of major ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous 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. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mancos Shale
The Mancos Shale or Mancos Group is a Late Cretaceous (Upper Cretaceous) geologic formation of the Western United States. The Mancos Shale was first described by Cross and Purington in 1899 and was named for exposures near the town of Mancos, Colorado. Geology The unit is dominated by mudrock that accumulated in offshore and marine environments of the Cretaceous North American Inland Sea. The Mancos was deposited during the Cenomanian (locally Albian) through Campanian ages, approximately from 95 million years ago ( Ma) to 80 Ma. Stratigraphically the Mancos Shale fills the interval between the Dakota and the Mesaverde Group. The lower marine Mancos Shale conformably intertongues with terrestrial sandstones and mudstones of the Dakota and in its upper part grades into and intertongues with the Mesaverde Group. The shale tongues typically have sharp basal contacts and gradational upper contacts. Whereas in the plains east of the Rocky Mountains certain mappable marine sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
