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Huayquerías Formation
The Huayquerías Formation ( es, Formación Huayquerías) is a Late Miocene fossiliferous geological formation of the Frontal Cordillera and Cuyo Basin of Argentina. The formation crops out in the central Mendoza Province. The formation, with a maximum thickness of , comprises reddish mudstones with thin beds of tuffs and sandstones, deposited in a fluvial, environment. The tuff in the formation is dated to 5.84 ± 0.41 Ma, placing it in the Huayquerian SALMA, the age named after the formation by Kraglievitch in 1934. The formation has provided fossils of the procyonid '' Cyonasua pascuali'' and the litoptern '' Huayqueriana cristata'', named after the formation. Description The Huayqueriás Formation, present in the Frontal Cordillera and the neighboring Cuyo Basin, was described in 1934 by Kraglievitch as the basis for the Huayquerian South American land mammal age. The name ''Huayquerías'' means "badlands".Forasiepi et al., 2016, p.1 The formation comprises reddish mudston ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messinian
The Messinian is in the geologic timescale the last age or uppermost stage of the Miocene. It spans the time between 7.246 ± 0.005 Ma and 5.333 ± 0.005 Ma (million years ago). It follows the Tortonian and is followed by the Zanclean, the first age of the Pliocene. The Messinian overlaps the Turolian European Land Mammal Mega Zone (more precisely MN 12 and 13) and the Pontian Central European Paratethys Stage. It also overlaps the late Huayquerian and early Montehermosan South American Land Mammal Ages, and falls inside the more extensive Hemphillian North American Land Mammal Age. During the Messinian, around 6 million years ago, the Messinian salinity crisis took place, which brought about repeated desiccations of the Mediterranean Sea. Definition The Messinian was introduced by Swiss stratigrapher Karl Mayer-Eymar in 1867. Its name comes from the Italian city of Messina on Sicily, where the Messinian evaporite deposit is of the same age. The base of the Messinian is at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) because they are the most resistant minerals to weathering processes at the Earth's surface. Like uncemented sand, sandstone may be any color due to impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions. Rock formations that are primarily composed of sandstone usually allow the percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Quartz-bearing sandstone can be changed into quartzite through metamorphism, usually related to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unconformity
An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger layer, but the term is used to describe any break in the sedimentary geologic record. The significance of angular unconformity (see below) was shown by James Hutton, who found examples of Hutton's Unconformity at Jedburgh in 1787 and at Siccar Point in 1788. The rocks above an unconformity are younger than the rocks beneath (unless the sequence has been overturned). An unconformity represents time during which no sediments were preserved in a region or were subsequently eroded before the next deposition. The local record for that time interval is missing and geologists must use other clues to discover that part of the geologic history of that area. The interval of geologic time not represented is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ashfall
The Ashfall Fossil Beds of Antelope County in northeastern Nebraska are rare fossil sites of the type called lagerstätten that, due to extraordinary local conditions, capture an ecological "snapshot" in time of a range of well-preserved fossilized organisms. Ash from a Yellowstone hotspot eruption 10-12 million years ago created these fossilized bone beds. The ash depth was up to 1 foot. The site is protected as Ashfall Fossil Beds State Historical Park, a park that includes a visitor center with interpretive displays and working fossil preparation laboratory, and a protected ongoing excavation site, the Hubbard Rhino Barn, featuring fossil ''Teleoceras'' (native hippo-like ancestral rhinoceros) and ancestral horses. The Ashfall Fossil Beds are especially famous for fossils of mammals from the middle Miocene geologic epoch. The Ashfall Fossil Beds are stratigraphically part of the Serravallian-age Ogallala Group. Bruneau-Jarbidge event The Ashfall deposit preserves the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 69,963 species described. Vertebrates comprise such groups as the following: * jawless fish, which include hagfish and lampreys * jawed vertebrates, which include: ** cartilaginous fish (sharks, rays, and ratfish) ** bony vertebrates, which include: *** ray-fins (the majority of living bony fish) *** lobe-fins, which include: **** coelacanths and lungfish **** tetrapods (limbed vertebrates) Extant vertebrates range in size from the frog species ''Paedophryne amauensis'', at as little as , to the blue whale, at up to . Vertebrates make up less than five percent of all described animal species; the rest are invertebrates, which lack vertebral columns. The vertebrates traditionally include the hagfish, which do no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichnofossil
A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils, which are the fossilized remains of parts of organisms' bodies, usually altered by later chemical activity or mineralization. The study of such trace fossils is ichnology and is the work of ichnologists. Trace fossils may consist of impressions made on or in the substrate by an organism. For example, burrows, borings ( bioerosion), urolites (erosion caused by evacuation of liquid wastes), footprints and feeding marks and root cavities may all be trace fossils. The term in its broadest sense also includes the remains of other organic material produced by an organism; for example coprolites (fossilized droppings) or chemical markers (sedimentological structures produced by biological means; for example, the formation of stromatolites). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleoburrow
A paleoburrow is an underground shelter (tunnel, burrow, lair, etc.) excavated by extinct paleo-vertebrate megafauna (i.e., giant mammals, such as ground sloths) that lived in the prehistory, prehistoric era. A crotovina is a paleoburrow filled with sediments (sands, clays, etc.) that have been deposited over the centuries through rainfall and accumulated due to the porosity of the terrain. Generally, fossils found in crotovinas exhibit large proportions similar to known megafauna of their geological period. In Brazil, hundreds of paleontological sites characterized as paleoburrows exist, such as in Ponta do Abunã, in Rondônia, within the Amazon region, in the Serra do Gandarela National Park, in Minas Gerais, in Monte Bonito, the southern Rio Grande do Sul}Rio Grande, as well as the Toca do Tatu in Santa Catarina (state), Santa Catarina. After the extinction of the megafauna about 10,000 years ago, some paleoburrows were reused by indigenous human populations. Recent searches in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mudcrack
Mudcracks (also known as mud cracks, desiccation cracks or cracked mud) are sedimentary structures formed as muddy sediment Desiccation, dries and contracts.Jackson, J.A., 1997, ''Glossary of Geology'' (4th ed.), American Geological Institute, Alexandria, VA, 769 p.Stow, D.A., 2005, ''Sedimentary Rocks in the Field'', Academic Press, London, 320 p. Crack formation also occurs in clay-bearing soils as a result of a reduction in water content. Formation of mudcrack Naturally forming mudcracks start as wet, muddy sediment desiccation, dries up and contracts. A strain is developed because the top layer shrinks while the material below stays the same size. When this strain becomes large enough, channel cracks form in the dried-up surface to relieve the strain. Individual cracks spread and join up, forming a polygonal, interconnected network of forms called "tesselations." If the strain continues to build the polygon start to curled upward. This characteristic can be used in geology t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Huayqueriana
''Huayqueriana'' is an extinct genus of South American litoptern, related to ''Macrauchenia'', and belonging to the same family, Macraucheniidae. It was formerly known as ''Macrauchenidia latidens'', described in 1939 by Cabrera, but redefined as ''Huayqueriana'' in 2016 based on the earlier name convention of Rovereto 1914.Forasiepi et al., 2016, p.11Cabrera (A.), 1939. Sobre vertebrados fósiles del Plioceno del Adolfo Alsina. ''Revista Museo de La Plata'', II (n. Serie), Paleont.: 3-35. The genus is named after the Huayquerías Formation and the eponymous Huayquerian South American land mammal age defined at the formation. Classification Cladogram based in the phylogenetic analysis In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ... published by Schmidt ''et al''., 2014, showi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Litopterna
Litopterna (from grc, λῑτή πτέρνα "smooth heel") is an extinct order of fossil hoofed mammals from the Cenozoic era. The order is one of the five great orders of South American ungulates that were endemic to the continent, until the Great American Biotic Interchange brought new ungulate species. Like other endemic South American mammals, their relationship to other mammal groups had long been unclear, but recent genetic and proteomic evidence indicates that their closest living relatives are Perissodactyls (odd-toed ungulates) including horses, rhinoceros, and tapirs, and that litopterns are closely related to notoungulates, another widespread group of South American ungulates. There were two major groups of litopterns: Proterotheriidae and Macraucheniidae. Proterotheriids were medium to large animals that evolved adaptations for fast running, and occupied a variety of niches that elsewhere were filled by animals such as goats and antelopes, mouse deer, and horses. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyonasua
''Cyonasua'' (meaning "dog-coati" in Greek) is an extinct genus of procyonid from the Late Miocene to Middle Pleistocene of South America. Fossils of ''Cyonasua'' have been found in Argentina ( Ituzaingó, Epecuén, Huayquerías, Monte Hermoso, Chapadmalal, Maimará, Ensenada, La Playa, Chiquimil, Andalhuala, and Cerro Azul Formations), Bolivia ( Tariquía Formation), Uruguay ( Camacho Formation), and Venezuela ( San Gregorio Formation). The oldest well-dated fossils of ''Cyonasua'' are approximately 7.3 million years old. Most fossils of ''Cyonasua'' are late Miocene to early late Pliocene (Huayquerian to Chapadmalalan SALMAs, 7.3-3 million years old) in age, but a single early Pleistocene specimen (the holotype and only known specimen of ''Cyonasua meranii'') indicates that members of this genus survived until at least 0.99 million years ago (the fossil layer where this specimen was collected dating to the Jaramillo Chron). ''Cyonasua'' is the oldest terrestrial carnivoran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procyonidae
Procyonidae is a New World family of the order Carnivora. It comprises the raccoons, ringtails, cacomistles, coatis, kinkajous, olingos, and olinguitos. Procyonids inhabit a wide range of environments and are generally omnivorous. Characteristics Procyonids are relatively small animals, with generally slender bodies and long tails, though the common raccoon tends to be bulky. Because of their general build, the Procyonidae are often popularly viewed as smaller cousins of the bear family. This is apparent in their German names: a raccoon is called a ''Waschbär'' (washing bear, as it "washes" its food before eating), a coati is a ''Nasenbär'' (nose-bear), while a kinkajou is a ''Honigbär'' (honey-bear). Dutch follows suit, calling the animals ''wasbeer'', ''neusbeer'' and ''rolstaartbeer'' respectively. However, it is now believed that procyonids are more closely related to mustelids than to bears. Procyonids share common morphological characteristics including a shortened ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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