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Jagüel Formation
The Jagüel Formation is a geological formation, located in Patagonia, Argentina. It underlies the Roca Formation and overlies the Allen Formation. All of these formations belong to the Malargüe Group. Its name was coined by Windhausen in 1914. This unit, defined in the eastern area of the Neuquén Embayment, registers an event of marine flooding that happened during the ages Maastrichtian and Danian.Rodríguez, María Fernanda (2011). «El Grupo Malargüe (Cretácico Tardío-Paleógeno Temprano) en la Cuenca Neuquina». ''Relatorio del XVIII Congreso Geológico Argentino'' (Neuquén): 245-264. It consists of mudrocks formed between the upper section or "Gypsum" of the Allen Formation, and the base of the first organogenic limestone of the Roca Formation. The Jagüel Formation is particularly important since a vast area of the formation contains the Cretaceous–Paleogene boundary that marks the end of the Mesozoic Era. It also shows evidence of the Cretaceous–Paleogene (K– ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malargüe Group
The Malargüe Group is a group of geologic formations of the Neuquén Basin of the Mendoza, Neuquén, Río Negro and La Pampa Provinces in northern Patagonia, Argentina. The formations of the Malargüe Group range in age between the middle Campanian to Deseadan, an Oligocene age of the SALMA classification, straddling the Cretaceous–Paleogene boundary, about 79 million to 30 million years in age. The group overlies the older Neuquén Group, separated by an unconformity dated to 79 Ma.Leanza et al., 2004, p.63 The rocks of the Malargüe Group comprise both marine and continental deposits which are over 400 m (1312 ft) thick in total. Subdivision The Malargüe Group is subdivided into: * Agua de la Piedra Formation (Deseadan) - white-grayish tuffs and tobaceous paleosols [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, the fourth-largest country in the Americas, and the eighth-largest country in the world. It shares the bulk of the Southern Cone with Chile to the west, and is also bordered by Bolivia and Paraguay to the north, Brazil to the northeast, Uruguay and the South Atlantic Ocean to the east, and the Drake Passage to the south. Argentina is a federal state subdivided into twenty-three provinces, and one autonomous city, which is the federal capital and largest city of the nation, Buenos Aires. The provinces and the capital have their own constitutions, but exist under a federal system. Argentina claims sovereignty over the Falkland Islands, South Georgia and the South Sandwich Islands, and a part of Antarctica. The earliest recorded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mudrock
Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone, slate, and shale. Most of the particles of which the stone is composed are less than and are too small to study readily in the field. At first sight, the rock types appear quite similar; however, there are important differences in composition and nomenclature. There has been a great deal of disagreement involving the classification of mudrocks. A few important hurdles to their classification include the following: # Mudrocks are the least understood and among the most understudied sedimentary rocks to date. # Studying mudrock constituents is difficult due to their diminutive size and susceptibility to weathering on outcrops. # And most importantly, scientists accept more than one classification scheme. Mudrocks make up 50% of the sedimentary rocks in the geologic record and are easily the most widespread deposits on Earth. Fine sedime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithology
The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples, or with low magnification microscopy. Physical characteristics include colour, texture, grain size, and composition. Lithology may refer to either a detailed description of these characteristics, or a summary of the gross physical character of a rock. Examples of lithologies in the second sense include sandstone, slate, basalt, or limestone. Lithology is the basis of subdividing rock sequences into individual lithostratigraphic units for the purposes of mapping and correlation between areas. In certain applications, such as site investigations, lithology is described using a standard terminology such as in the European geotechnical standard Eurocode 7. Rock type The naming of a lithology is based on the rock type. The three major rock types are igneous, sedimentary, and metamorphic. Igneous rocks are formed directly from magma, which is a mixture of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Casa De Piedra, La Pampa
Casa de Piedra (La Pampa) is a village and rural locality (municipality) in La Pampa Province in Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, t .... Climate References {{coord, 38, 09, 26, S, 67, 08, 51, W, type:city_source:kolossus-eswiki, display=title Populated places in La Pampa Province ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Roca, Río Negro
General Roca is a city in the northeast of the Argentine province of Río Negro, northern Patagonia. It was founded on September 1, 1879, by Colonel Lorenzo Vintter, on the order of War Minister Julio A. Roca, during the Conquest of the Desert. The place of the first settlement was known by native mapuche people as Fiske Menuco, which means "deep water". It was destroyed in 1899 by a flooding of the Río Negro, and had to be rebuilt northwest in higher lands. Its present population is approximately 86,000 (according to ), making it the second most populated city in the province after Bariloche, and the second most important in the Alto Valle after Neuquén. The main activity around the city is the intensive agriculture under irrigation, which made possible an intense agro-industrial activity. The main crops are pears and apples. The city hosts the annual National Festival of the Apple, which is held in early February. General Roca, named after Julio A. Roca, is located from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pellegrini Lake
The Pellegrini Lake is an artificial lake located on the Argentinian Patagonia, in the province of Río Negro, near the city of Cinco Saltos, at approximately and 270 m above mean sea level. This reservoir was originally a natural depressed area, possibly excavated by wind erosion, which was later filled with water brought by a derivation channel from the nearby Neuquén River, in order to regulate its flow (since the river had no natural lakes that would fulfill this function). It has mean and maximum depths of 9.4 and 18 m, respectively. It covers an area of 112 km² and has a volume of 1.053×109 m³. The lake is employed for commercial fishing of ''trucha criolla'' (''Percichthys trucha'', a species of temperate perch) and ''pejerrey'' (''Odontesthes microlepidotus'', a neotropical silverside The Neotropical silversides are a family, Atherinopsidae, of fishes in the order Atheriniformes. About 112 species in 13 genera are distributed throughout the tropical and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micropaleontology
Micropaleontology (American spelling; spelled micropalaeontology in European usage) is the branch of paleontology ( palaeontology) that studies microfossils, or fossils that require the use of a microscope to see the organism, its morphology and its characteristic details. Microfossils Microfossils are fossils that are generally between 0.001mm and 1 mm in size, the study of which requires the use of light or electron microscopy. Fossils which can be studied by the naked eye or low-powered magnification, such as a hand lens, are referred to as macrofossils. For example, some colonial organisms, such as Bryozoa (especially the Cheilostomata) have relatively large colonies, but are classified by fine skeletal details of the small individuals of the colony. In another example, many fossil genera of Foraminifera, which are protists are known from shells (called "tests") that were as big as coins, such as the genus '' Nummulites''. Microfossils are a common feature o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonoidea
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Reptile
Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in a marine environment. The earliest marine reptile mesosaurus (not to be confused with mosasaurus), arose in the Permian period during the Paleozoic era. During the Mesozoic era, many groups of reptiles became adapted to life in the seas, including such familiar clades as the ichthyosaurs, plesiosaurs (these two orders were once thought united in the group "Enaliosauria", a classification now cladistically obsolete), mosasaurs, nothosaurs, placodonts, sea turtles, thalattosaurs and thalattosuchians. Most marine reptile groups became extinct at the end of the Cretaceous period, but some still existed during the Cenozoic, most importantly the sea turtles. Other Cenozoic marine reptiles included the bothremydids, palaeophiid snakes, a few choristoderes such as '' Simoedosaurus'' and dyrosaurid crocodylomorphs. Various types of marine gavialid crocodilians remaine ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
