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South Polar Region Of The Cretaceous
The South Polar region of the Cretaceous comprised the continent of East Gondwana–modern day Australia, Zealandia, and Antarctica–a product of the break-up of Gondwana in the Cretaceous Period. The southern region, during this time, was much warmer than it is today, ranging from perhaps in the latest Cretaceous Maastrichtian in what is now southeastern Australia. This prevented permanent ice sheets from developing and fostered polar forests, which were largely dominated by conifers, cycads, and ferns, and relied on a temperate climate and heavy rainfall. Major fossil-bearing geological formations that record this area are: the Santa Marta and Sobral Formations of Seymour Island off the Antarctic Peninsula; the Snow Hill Island, Lopez de Bertodano, and the Hidden Lake Formations on James Ross Island also off the Antarctic Peninsula; and the Eumeralla and Wonthaggi Formations in Australia. The South Polar region housed many endemic species, including several relict forms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hidden Lake Formation
The Hidden Lake Formation is a Late Cretaceous geologic formation in Antarctica. The sandstones and siltstones of the formation were deposited in a deltaic environment. Indeterminate megalosaur remains have been recovered from it.Weishampel, et al. (2004). "Dinosaur distribution" pp. 517–607. in Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): ''The Dinosauria'', 2nd, Berkeley: University of California Press. 861 pp. . " pp. 517–607. Also many plant fossils and ichnofossils of '' Planolites sp.'' and '' Palaeophycus sp.'' have been found in the formation.Hidden Lake at .org Paleofauna * |
Magmatism
Magmatism is the emplacement of magma within and at the surface of the outer layers of a terrestrial planet, which solidifies as igneous rocks. It does so through magmatic activity or igneous activity, the production, intrusion and extrusion of magma or lava. Volcanism is the surface expression of magmatism. Magmatism is one of the main processes responsible for mountain formation. The nature of magmatism depends on the tectonic setting. For example, andesitic magmatism is associated with the formation of island arcs at convergent plate boundaries while basaltic magmatism is found at mid-ocean ridges during sea-floor spreading at divergent plate boundaries. On Earth, magma forms by partial melting of silicate rocks either in the mantle, continental or oceanic crust. Evidence for magmatic activity is usually found in the form of igneous rocks formed from magma. Convergent boundaries Magmatism is associated with all stages of the development of convergent plate boundar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Rock
Volcanic rocks (often shortened to volcanics in scientific contexts) are rocks formed from lava erupted from a volcano. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and metamorphic rocks and constitute an important element of some sediments and sedimentary rocks. For these reasons, in geology, volcanics and shallow hypabyssal rocks are not always treated as distinct. In the context of Precambrian shield geology, the term "volcanic" is often applied to what are strictly metavolcanic rocks. Volcanic rocks and sediment that form from magma erupted into the air are called "pyroclastics," and these are also technically sedimentary rocks. Volcanic rocks are among the most common rock types on Earth's surface, particularly in the oceans. On land, they are very common at plate boundaries and in flood basalt provinces. It has been estimated that volcanic rocks cover about 8% of the Earth's current land surface. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palmer Land
Palmer Land () is the portion of the Antarctic Peninsula, Antarctica that lies south of a line joining Cape Jeremy and Cape Agassiz. This application of Palmer Land is consistent with the 1964 agreement between the Advisory Committee on Antarctic Names and the UK Antarctic Place-Names Committee, in which the name Antarctic Peninsula was approved for the major peninsula of Antarctica, and the names Graham Land and Palmer Land for the northern and southern portions, respectively. The line dividing them is roughly 69° S. Boundaries In its southern extreme, the Antarctic Peninsula stretches west, with Palmer Land eventually bordering Ellsworth Land along the 80° W line of longitude. Palmer Land is bounded in the south by the ice-covered Carlson Inlet, an arm of the Filchner–Ronne Ice Shelf, Filchner-Ronne Ice Shelf, which crosses the 80° W line. This is the base of Cetus Hill. This feature is named after Nathaniel Palmer, an American sealer who explored the Antarctic Peninsula a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Koolasuchus
''Koolasuchus'' is an extinct genus of brachyopoid temnospondyl in the family Chigutisauridae. Fossils have been found from Victoria, Australia and date back 125-120 million years ago to Barremian-Aptian stages of the Early Cretaceous. ''Koolasuchus'' is the youngest known temnospondyl. It is known from several fragments of the skull and other bones such as vertebrae, ribs, and pectoral elements. The type species ''Koolasuchus cleelandi'' was named in 1997. ''K. cleelandi'' was adopted as the fossil emblem for the state of Victoria, Australia on 13 January 2022. History Between 1978 and 1979, a fossil expedition by the National Museum of Victoria explored fossiliferous outcrops belonging to the Strzelecki Group in Kilcunda, Victoria, Australia. In 1979 during the expedition, a pair of incomplete mandibles (lower jaws) of an unidentified tetrapod was unearthed from strata deriving from the upper Barremian-aged Wonthaggi Formation at a site dubbed "Rowells Beach". This spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Labyrinthodont
"Labyrinthodontia" (Greek, 'maze-toothed') is an informal grouping of extinct predatory amphibians which were major components of ecosystems in the late Paleozoic and early Mesozoic eras (about 390 to 150 million years ago). Traditionally considered a subclass of the class Amphibia, modern classification systems recognize that labyrinthodonts are not a formal natural group (clade) exclusive of other tetrapods. Instead, they consistute an evolutionary grade (a paraphyletic group), ancestral to living tetrapods such as lissamphibians (modern amphibians) and amniotes (reptiles, mammals, and kin). "Labyrinthodont"-grade vertebrates evolved from lobe-finned fishes in the Devonian, though a formal boundary between fish and amphibian is difficult to define at this point in time. "Labyrinthodont" generally refers to extinct four-limbed tetrapods with a large body size and a crocodile-like lifestyle. The name describes the pattern of infolding of the dentin and enamel of the teeth, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypsilophodont
Hypsilophodontidae (or Hypsilophodontia) is a traditionally used family of ornithopod dinosaurs, generally considered invalid today. It historically included many small bodied bipedal neornithischian taxa from around the world, and spanning from the Middle Jurassic until the Late Cretaceous. This inclusive status was supported by some phylogenetic analyses from the 1990s and mid 2000s, although there have also been many finding that the family is an unnatural grouping which should only include the type genus, ''Hypsilophodon'', with the other genera being within clades like Thescelosauridae and Elasmaria. A 2014 analysis by Norman recovered a grouping of ''Hypsilophodon'', Rhabdodontidae and ''Tenontosaurus'', which he referred to as Hypsilophodontia. That clade is formally defined in the ''PhyloCode'' as "the smallest clade within Ornithopoda containing ''Hypsilophodon foxii'' and '' Tenontosaurus tilletti'' provided it does not include '' Iguanodon bernissartensis''". All other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relict (biology)
In biogeography and paleontology, a relict is a population or taxon of organisms that was more widespread or more diverse in the past. A relictual population is a population currently inhabiting a restricted area whose range was far wider during a previous geologic epoch. Similarly, a relictual taxon is a taxon (e.g. species or other lineage) which is the sole surviving representative of a formerly diverse group. Definition A relict (or relic) plant or animal is a taxon that persists as a remnant of what was once a diverse and widespread population. Relictualism occurs when a widespread habitat or range changes and a small area becomes cut off from the whole. A subset of the population is then confined to the available hospitable area, and survives there while the broader population either shrinks or evolves divergently. This phenomenon differs from endemism in that the range of the population was not always restricted to the local region. In other words, the species or group did ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemic (ecology)
Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be ''endemic'' to that particular part of the world. An endemic species can also be referred to as an ''endemism'' or, in scientific literature, as an ''endemite''. Similarly, many species found in the Western ghats of India are examples of endemism. Endemism is an important concept in conservation biology for measuring biodiversity in a particular place and evaluating the risk of extinction for species. Endemism is also of interest in evolutionary biology, because it provides clues about how changes in the environment cause species to undergo range shifts (potentially expanding their range into a larger area or bec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
