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Orsten
The Orsten fauna are fossilized organisms preserved in the Orsten lagerstätten of Cambrian (Late Miaolingian to Furongian) rocks, notably at Kinnekulle and on the island of Öland, all in Sweden. The initial site, discovered in 1975 by Klaus Müller and his assistants, exceptionally preserves soft-bodied organisms, and their larvae, who are preserved uncompacted in three dimensions. The fossils are phosphatized and silicified, thus the delicate chitinous cuticle and soft parts are not affected by acids, which act upon the limestone nodules within which the fossils have survived. Acids dissolve the limestone, revealing the microfossils in a recovery process called "acid etching". To recover the fossils, more than one and a half tons of Orsten limestone have been dissolved in acid, originally in a specifically designed laboratory in Bonn, more recently moved to Ulm. The insoluble residue is scanned by electron microscope. The phosphorus used to replace the fossils with calcium p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagerstätte
A Lagerstätte (, from '' Lager'' 'storage, lair' '' Stätte'' 'place'; plural ''Lagerstätten'') is a sedimentary deposit that exhibits extraordinary fossils with exceptional preservation—sometimes including preserved soft tissues. These formations may have resulted from carcass burial in an anoxic environment with minimal bacteria, thus delaying the decomposition of both gross and fine biological features until long after a durable impression was created in the surrounding matrix. ''Lagerstätten'' span geological time from the Neoproterozoic era to the present. Worldwide, some of the best examples of near-perfect fossilization are the Cambrian Maotianshan shales and Burgess Shale, the Silurian Waukesha Biota, the Devonian Hunsrück Slates and Gogo Formation, the Carboniferous Mazon Creek, the Jurassic Posidonia Shale and Solnhofen Limestone, the Cretaceous Yixian, Santana, and Agua Nueva formations, the Eocene Green River Formation, the Miocene Foulden Maar an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agnostus
''Agnostus'' is a genus of agnostid trilobites, belonging to the family Agnostidae, that lived during the late Middle Cambrian – early Upper Cambrian (about 506 to 492 million years ago). It is the type genus of the family Agnostidae and is subdivided into two subgenera, ''Agnostus'' and ''Homagnostus''. Etymology ''Agnostus'' is from the Ancient Greek άγνωστος (''ágnostos'') "unknown", and reflects the fact that early paleontologists did not know what type of animal with which they were confronted. The species epithet has this origin: * ''pisiformis'' derives from the Latin ''pīsum'' which means "pea", and ''forma'' meaning "shape", for its globe-like appearance when rolled. Description ] Like all Agnostida, ''Agnostus'' is diminutive and the headshield (or Cephalon (arthropod head)#Trilobites, cephalon) and tailshield (or pygidium) are around the same size (or isopygous) and outline. As in all Agnostina, ''Agnostus'' has two thorax segments. When Agnostina ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alum Shale Formation
The Alum Shale Formation (also known as alum schist and alum slate) is a formation of black shale of Middle Cambrian to Tremadocian (Lower Ordovician) in age found predominantly in southern Scandinavia. It is shale or clay slate containing pyrite. Decomposition of pyrite by weathering forms sulfuric acid, which acts on potash and alumina constituents to form alum, which often occurs as efflorescences on the rock outcrop. As the formation contains kerogen originated from algae, it is also classified as marinite-type oil shale. At the same time it is rich in aromatic hydrocarbon attributed to post-depositional irradiation damage to saturated hydrocarbons, induced by uranium concentration in the shale. Alum shale also contains enhanced levels of radium as a result of uranium decay. Between 1950 and 1989, Sweden used alum shale for the uranium production. See also *Orsten, a lagerstätte A Lagerstätte (, from '' Lager'' 'storage, lair' '' Stätte'' 'place'; plural ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentastomid
The Pentastomida are an enigmatic group of parasitic arthropods commonly known as tongue worms due to the resemblance of the species of the genus ''Linguatula'' to a vertebrate tongue; molecular studies point to them being degenerate crustaceans. About 130 species of pentastomids are known; all are obligate parasites with correspondingly degenerate anatomy. Adult tongue worms vary from about in length, and parasitise the respiratory tracts of vertebrates. They have five anterior appendages. One is the mouth; the others are two pairs of hooks, which they use to attach to the host. This arrangement led to their scientific name, meaning "five openings", but although the appendages are similar in some species, only one is a mouth. Taxonomy Historically significant accounts of tongue worm biology and systematics include early work by Josef Aloys Frölich, Alexander von Humboldt, Karl Asmund Rudolphi, Karl Moriz Diesing and Rudolph Leuckart. Other important summaries have been publ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tardigrade
Tardigrades (), known colloquially as water bears or moss piglets, are a phylum of eight-legged segmented micro-animals. They were first described by the German zoologist Johann August Ephraim Goeze in 1773, who called them Kleiner Wasserbär ("little water bear"). In 1777, the Italian biologist Lazzaro Spallanzani named them Tardigrada (), which means "slow steppers". They have been found in diverse regions of Earth's biospheremountaintops, the deep sea, tropical rainforests, and the Antarctic. Tardigrades are among the most resilient animals known, with individual species able to survive extreme conditions – such as exposure to extreme temperatures, extreme pressures (both high and low), air deprivation, radiation, dehydration, and starvation – that would quickly kill most other known forms of life. Tardigrades have survived exposure to outer space. There are about 1,300 known species in the phylum Tardigrada, a part of the superphylum Ecdysozoa consisting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microfossil
A microfossil is a fossil that is generally between 0.001 mm and 1 mm in size, the visual study of which requires the use of light or electron microscopy. A fossil which can be studied with the naked eye or low-powered magnification, such as a hand lens, is referred to as a macrofossil. Microfossils are a common feature of the geological record, from the Precambrian to the Holocene. They are most common in deposits of marine environments, but also occur in brackish water, fresh water and terrestrial sedimentary deposits. While every kingdom of life is represented in the microfossil record, the most abundant forms are protist skeletons or microbial cysts from the Chrysophyta, Pyrrhophyta, Sarcodina, acritarchs and chitinozoans, together with pollen and spores from the vascular plants. Overview A microfossil is a descriptive term applied to fossilized plants and animals whose size is just at or below the level at which the fossil can be analyzed by the naked eye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Territory
The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an Australian territory in the central and central northern regions of Australia. The Northern Territory shares its borders with Western Australia to the west ( 129th meridian east), South Australia to the south ( 26th parallel south), and Queensland to the east ( 138th meridian east). To the north, the territory looks out to the Timor Sea, the Arafura Sea and the Gulf of Carpentaria, including Western New Guinea and other islands of the Indonesian archipelago. The NT covers , making it the third-largest Australian federal division, and the 11th-largest country subdivision in the world. It is sparsely populated, with a population of only 249,000 – fewer than half as many people as in Tasmania. The largest population center is the capital city of Darwin. The archaeological history of the Northern Territory may have begun more than 60,000 years ago when humans first sett ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flocculation
Flocculation, in the field of chemistry, is a process by which colloidal particles come out of suspension to sediment under the form of floc or flake, either spontaneously or due to the addition of a clarifying agent. The action differs from precipitation in that, prior to flocculation, colloids are merely suspended, under the form of a stable dispersion (where the internal phase (solid) is dispersed throughout the external phase (fluid) through mechanical agitation) and are not truly dissolved in solution. Coagulation and flocculation are important processes in water treatment with coagulation aimed to destabilize and aggregate particles through chemical interactions between the coagulant and colloids, and flocculation to sediment the destabilized particles by causing their aggregation into floc. Term definition According to the IUPAC definition, flocculation is "a process of contact and adhesion whereby the particles of a dispersion form larger-size clusters". Flocculatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrite
The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic Luster (mineralogy), luster and pale brass-yellow hue give it a superficial resemblance to gold, hence the well-known nickname of ''fool's gold''. The color has also led to the nicknames ''brass'', ''brazzle'', and ''Brazil'', primarily used to refer to pyrite found in coal. The name ''pyrite'' is derived from the Greek language, Greek (), 'stone or mineral which strikes fire', in turn from (), 'fire'. In ancient Roman times, this name was applied to several types of stone that would create sparks when struck against steel; Pliny the Elder described one of them as being brassy, almost certainly a reference to what we now call pyrite. By Georgius Agricola's time, , the term had become a generic term for all of the pyrite group, sulfide minerals. Pyrite is usua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shale
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite.Blatt, Harvey and Robert J. Tracy (1996) ''Petrology: Igneous, Sedimentary and Metamorphic'', 2nd ed., Freeman, pp. 281–292 Shale is characterized by its tendency to split into thin layers ( laminae) less than one centimeter in thickness. This property is called '' fissility''. Shale is the most common sedimentary rock. The term ''shale'' is sometimes applied more broadly, as essentially a synonym for mudrock, rather than in the more narrow sense of clay-rich fissile mudrock. Texture Shale typically exhibits varying degrees of fissility. Because of the parallel orientation of clay mineral flakes in shale, it breaks into thin layers, often splintery and usually parallel to the otherwise indistinguishable bedding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alum
An alum () is a type of chemical compound, usually a hydrated double sulfate salt of aluminium with the general formula , where is a monovalent cation such as potassium or ammonium. By itself, "alum" often refers to potassium alum, with the formula . Other alums are named after the monovalent ion, such as sodium alum and ammonium alum. The name "alum" is also used, more generally, for salts with the same formula and structure, except that aluminium is replaced by another trivalent metal ion like chromium, and/or sulfur is replaced by another chalcogen like selenium. The most common of these analogs is chrome alum . In most industries, the name "alum" (or "papermaker's alum") is used to refer to aluminium sulfate, , which is used for most industrial flocculation (the variable is an integer whose size depends on the amount of water absorbed into the alum). In medicine, "alum" may also refer to aluminium hydroxide gel used as a vaccine adjuvant. History Alum found at ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meiofauna
Meiobenthos, also called meiofauna, are small benthic invertebrates that live in both marine and fresh water environments. The term ''meiofauna'' loosely defines a group of organisms by their size, larger than microfauna but smaller than macrofauna, rather than a taxonomic grouping. In practice, that is organisms that can pass through a 1 mm mesh but will be retained by a 45 μm mesh, but the exact dimensions will vary from researcher to researcher. Whether an organism will pass through a 1 mm mesh will also depend upon whether it is alive or dead at the time of sorting. The term ''meiobenthos'' was first coined in 1942 by Mare, but organisms that would fit into the meiofauna category have been studied since the 18th century. A comprehensive text on meiofauna is ''Introduction to the study of meiofauna'' by Higgins and Thiel (1988). Meiofaunal taxa File:Ammonia tepida.jpg, Live foraminifera '' Ammonia tepida'' (Rotaliida) File:Waterbear.jpg, Water bear '' H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
