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Ivanovia
''Ivanovia'' is an extinct genus of marine green algae belonging to the order Bryopsidales and family Codiaceae. Species belonging to the genus lived from the Pennsylvanian to the Permian and have been found in the Moscow basin, North America, Italy, Tunisia, and China. Members of the genus have thalli (leaflike photosynthetic structures) that are cyathiform (cuplike in shape.) There are indications that asexual reproduction took place through budding of the thalli. Sexual reproduction also took place, through reproductive structures in stalked outgrowths of the thalli (oogonia and gametangia, the female and male reproductive structures of green algae.) Bioherms (fossil algal mounds) constructed by ''Ivanovia'' are prominent in the Paradox Formation of the Colorado Plateau, where they are important petroleum reservoir A petroleum reservoir or oil and gas reservoir is a subsurface accumulation of hydrocarbons contained in porous or fractured rock formations. Such reservoirs fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taphotaxon
A taphotaxon (from the Greek ταφος, ''taphos'' meaning ''burial'' and ταξις, ''taxis'' meaning ''ordering'') is an invalid taxon based on fossils remains that have been altered in a characteristic way during burial and diagenesis. The fossils so altered have distinctive characteristics that make them appear to be a new taxon, but these characteristics are spurious and do not reflect any significant taxonomic distinction from an existing fossil taxon. The term was first proposed by Spencer G. Lucas in 2001, who particularly applied it to spurious ichnotaxons, but it has since been applied to body fossils such as ''Nuia'' (interpreted as cylindrical oncolites formed around filamentous cyanobacteria) or '' Ivanovia'' (thought to be a taphotaxon of '' Anchicondium '' or '' Eugonophyllum''); conulariids, and crustaceans Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, rem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Codiaceae
Codiaceae is a family of green algae in the order Bryopsidales. Genera * † '' Abacella'' Maslov * '' Appeninocodium'' O.Dragastan * ''Arabicodium'' G.F.Elliott * '' Bevocastria'' E.J.Garwood * '' Botryella'' V.P.Shuysky * '' Boueina'' F.Toula * ''Codium'' Stackhouse * '' Garwoodia'' Alan Wood * ''Geppella'' Børgesen * ''Hedstroemia'' A.Rothpletz * ''Ivanovia ''Ivanovia'' is an extinct genus of marine green algae belonging to the order Bryopsidales and family Codiaceae. Species belonging to the genus lived from the Pennsylvanian to the Permian and have been found in the Moscow basin, North America, ...'' Khvorova * '' Johnsonicodium'' O.Dragastan * '' Neoanchicodium'' R.Endô * '' Scotlandella'' O.Dragastan * '' Succodium'' Konishi * '' Tethysicodium'' O.Dragastan Synonyms: * '' Acanthocodium'' * '' Agardhia'' A.Cabrera, 1823, nom. illeg., currently regarded as a synonym of Codium. * '' Lamarckia'' Olivi, 1792, nom. rejic., currently regarded as a synon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paradox Formation
In geology, the Paradox Formation Is a Pennsylvanian age formation which consists of abundant evaporites with lesser interbedded shale, sandstone, and limestone. The evaporites are largely composed of gypsum, anhydrite, and halite. The formation is found mostly in the subsurface, but there are scattered exposures in anticlines in eastern Utah and western Colorado. These surface exposures occur in the Black Mesa, San Juan and Paradox Basins and the formation is found in the subsurface in southwestern Colorado, southeastern Utah, northeastern Arizona and northeastern New Mexico. The formation is notable both for its petroleum resources and for its salt tectonics, which are responsible for many distinctive geologic features of the eastern Colorado Plateau. In addition to the anticline valleys, these include the grabens of the Needles District of Canyonlands National Park and the fins and arches of Arches National Park. Description The Paradox Formation was deposited in the Para ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pennsylvanian (geology)
The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, in the International Commission on Stratigraphy, ICS geologic timescale, the younger of two period (geology), subperiods (or upper of two system (stratigraphy), subsystems) of the Carboniferous Period. It lasted from roughly . As with most other geochronology, geochronologic units, the stratum, rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain by a few hundred thousand years. The Pennsylvanian is named after the U.S. state of Pennsylvania, where the coal-productive beds of this age are widespread. The division between Pennsylvanian and Mississippian (geology), Mississippian comes from North American stratigraphy. In North America, where the early Carboniferous beds are primarily marine limestones, the Pennsylvanian was in the past treated as a full-fledged geologic period between the Mississippian and the Permian. In parts of Europe, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gametangia
A gametangium (plural: gametangia) is an organ or cell in which gametes are produced that is found in many multicellular protists, algae, fungi, and the gametophytes of plants. In contrast to gametogenesis in animals, a gametangium is a haploid structure and formation of gametes does not involve meiosis. Types of gametangia Depending on the type of gamete produced in a gametangium, several types can be distinguished. Female Female gametangia are most commonly called archegonia. They produce egg cells and are the sites for fertilization. Archegonia are common in algae and primitive plants as well as gymnosperms. In flowering plants, they are replaced by the embryo sac inside the ovule. Male The male gametangia are most commonly called antheridia. They produce sperm cells that they release for fertilization. Antheridia producing non-motile sperm (spermatia) are called spermatangia. Some antheridia do not release their sperm. For example, the oomycete antheridium is a syncytium wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eugonophyllum
''Eugonophyllum'' is a genus of green algae in the family Halimedaceae. Specimens have been found in Carboniferous to Permian beds in North America, Europe, and east Asia. The alga is phylloid, meaning it has leaflike photosynthesizing structures called ''thalli'' (singular: ''thallus''). A thallus has the form of a broad, undulating blade, with circular to oval perforations scattered randomly across the blade. The blade consists of a fibrous medulla enclosed in a two-layered cortex. The thicker inner cortex consists of anastomosing utricles; that is, small sacklike structures joined by openings to their neighbors. The thin outer cortex consists of branchlets extending outwards from the inner cortex. Reproductive organs take the form of spherical protuberances within the inner cortex that are scattered irregularly over the surface of the thallus. The alga is calcareous and its remains are important components of carbonate rock beds of Pennsylvanian to early Permian. It is parti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petroleum Reservoir
A petroleum reservoir or oil and gas reservoir is a subsurface accumulation of hydrocarbons contained in porous or fractured rock formations. Such reservoirs form when kerogen (ancient plant matter) is created in surrounding rock by the presence of high heat and pressure in the Earth's crust. Petroleum reservoirs are broadly classified as ''conventional'' and '' unconventional'' reservoirs. In conventional reservoirs, the naturally occurring hydrocarbons, such as crude oil or natural gas, are trapped by overlying rock formations with lower permeability, while in unconventional reservoirs, the rocks have high porosity and low permeability, which keeps the hydrocarbons trapped in place, therefore not requiring a cap rock. Reservoirs are found using hydrocarbon exploration methods. Oil field An oil field is an area of accumulation of liquid oil underground in multiple (potentially linked) reservoirs, trapped as it rises by impermeable rock formations. In industrial terms, an o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colorado Plateau
The Colorado Plateau, also known as the Colorado Plateau Province, is a physiographic and desert region of the Intermontane Plateaus, roughly centered on the Four Corners region of the southwestern United States. This province covers an area of 336,700 km2 (130,000 mi2) within western Colorado, northwestern New Mexico, southern and eastern Utah, northern Arizona, and a tiny fraction in the extreme southeast of Nevada. About 90% of the area is drained by the Colorado River and its main tributaries: the Green, San Juan, and Little Colorado. Most of the remainder of the plateau is drained by the Rio Grande and its tributaries. The Colorado Plateau is largely made up of high desert, with scattered areas of forests. In the south-west corner of the Colorado Plateau lies the Grand Canyon of the Colorado River. Much of the Plateau's landscape is related to the Grand Canyon in both appearance and geologic history. The nickname "Red Rock Country" suggests the brightly colored ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thallus
Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms were previously known as the thallophytes, a polyphyletic group of distantly related organisms. An organism or structure resembling a thallus is called thalloid, thallodal, thalliform, thalline, or thallose. A thallus usually names the entire body of a multicellular non-moving organism in which there is no organization of the tissues into organs. Even though thalli do not have organized and distinct parts (leaves, roots, and stems) as do the vascular plants, they may have analogous structures that resemble their vascular "equivalents". The analogous structures have similar function or macroscopic structure, but different microscopic structure; for example, no thallus has vascular tissue. In exceptional cases such as the Lemnoideae, where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oogonia
An oogonium (plural oogonia) is a small diploid cell which, upon maturation, forms a primordial follicle in a female fetus or the female (haploid or diploid) gametangium of certain thallophytes. In the mammalian fetus Oogonia are formed in large numbers by mitosis early in fetal development from primordial germ cells. In humans they start to develop between weeks 4 and 8 and are present in the fetus between weeks 5 and 30. Structure Normal oogonia in human ovaries are spherical or ovoid in shape and are found amongst neighboring somatic cells and oocytes at different phases of development. Oogonia can be distinguished from neighboring somatic cells, under an electron microscope, by observing their nuclei. Oogonial nuclei contain randomly dispersed fibrillar and granular material whereas the somatic cells have a more condensed nucleus that creates a darker outline under the microscope. Oogonial nuclei also contain dense prominent nucleoli. The chromosomal material in the nucleu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triassic
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period of the Mesozoic Era. Both the start and end of the period are marked by major extinction events. The Triassic Period is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic. The Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished; it was well into the middle of the Triassic before life recovered its former diversity. Three categories of organisms can be distinguished in the Triassic record: survivors from the extinction event, new groups that flourished briefly, and other new groups that went on to dominate the Mesozoic Era. Reptiles, especially archosaurs, were the chief terrestrial vertebrates during this time. A specialized subgroup of archo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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