|
Neuquén Group
The Neuquén Group is a group of geologic formations found in Argentina. Rocks in the Neuquén Group fall within the Cenomanian to early Campanian stages of the Late Cretaceous Period. It overlies the older Lohan Cura Formation and is itself overlain by the younger Allen Formation of the Malargüe Group, separated from both by unconformities, dated to 98 and 79 Ma respectively.Leanza et al., 2004, p.63 Description Deposits have been located in the provinces of Río Negro, Neuquén, and Mendoza. Although several different types of environments are represented in various sections of the Neuquén Group, the dominant regime is alluvial deposition. Many dinosaur and other fossil types have been discovered in these sediments. Subdivision There are seven formations within the Neuquén Group. These are divided into three subgroups named after major rivers in the area. In some works, the subgroups themselves are treated as formations and what usually is considered to be the formatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cenomanian
The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding age. Both age and stage bear the same name. As a unit of geologic time measure, the Cenomanian Age spans the time between 100.5 and 93.9 million years ago (Mya). In the geologic timescale, it is preceded by the Albian and is followed by the Turonian. The Upper Cenomanian starts around at 95 Mya. The Cenomanian is coeval with the Woodbinian of the regional timescale of the Gulf of Mexico and the early part of the Eaglefordian of the regional timescale of the East Coast of the United States. At the end of the Cenomanian, an anoxic event took place, called the Cenomanian-Turonian boundary event or the "Bonarelli event", that is associated with a minor extinction event for marine spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lisandro Formation
__NOTOC__ The Lisandro Formation, alternatively known as the Cerro Lisandro Formation, is a Late Cretaceous ( Late Cenomanian to Early Turonian) geologic formation with outcrops in the Neuquén, Río Negro and Mendoza Provinces of Argentina. It is the youngest formation within the Río Limay Subgroup, the lowest section of the Neuquén Group. Formerly that subgroup was treated as a formation, and the Lisandro Formation was known as the (Cerro) Lisandro Member.Sánchez ''et al.'', 2006 The type locality of the Lisandro Formation is the hill known as Cerro Lisandro in Neuquén Province. This formation conformably overlies the Huincul Formation, and it is in turn overlain by the Portezuelo Formation, which is a part of the Río Neuquén Subgroup. The Lisandro Formation varies between thick, the thinnest of the three formations in its subgroup. It is composed of siltstones and claystones, red in color, which have been interpreted as a swampy to fluvial environment. Usually, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the Latin word for the white limestone known as chalk. The chalk of northern France and the white cliffs of south-eastern England date from the Cretaceous Period. Climate During the Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Geography Due to plate tectonics, the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia. India maintained a northward course towards Asia. In the Southern Hemisphere, Australia and Ant ... [...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 human prese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by Abraham Gottlob Wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Unit
A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features (facies) that characterize it. Units must be ''mappable'' and ''distinct'' from one another, but the contact need not be particularly distinct. For instance, a unit may be defined by terms such as "when the sandstone component exceeds 75%". Lithostratigraphic units Sequences of sedimentary and volcanic rocks are subdivided the basis of their shared or associated lithology. Formally identified lithostratigraphic units are structured in a hierarchy of lithostratigraphic rank, higher rank units generally comprising two or more units of lower rank. Going from smaller to larger in rank, the main lithostratigraphic ranks are Bed, Member, Formation, Group and Supergroup. Formal names of lithostratigraphic units are assigned by geological surveys. Units of formation or hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuquén
Neuquén (; arn, Nehuenken) is the capital city of the Argentine province of Neuquén and of the Confluencia Department, located in the east of the province. It occupies a strip of land west of the confluence of the Limay and Neuquén rivers which form the Río Negro, making it part of the ecoregion of Alto Valle del Río Negro. The city and surrounding area have a population of more than 340,000, making it the largest city in Patagonia. Along with the cities of Plottier and Cipolletti, it is part of the Neuquén – Plottier – Cipolletti conurbation. Founded in 1904, it is the newest provincial capital city in Argentina. Etymology The name of the city comes from the Neuquén River, which in Mapuche language means "water that has strength". This name was already used since 1884 for the federal territory. Since 1902, it was used for the railway station of the town, which at that time was a hamlet called Confluencia. The name of the town was officially chosen in 1904, when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuquén Basin
Neuquén Basin ( es, Cuenca Neuquina) is a sedimentary basin covering most of Neuquén Province in Argentina. The basin originated in the Jurassic and developed through alternating continental and marine conditions well into the Tertiary. The basin bounds to the west with the Andean Volcanic Belt, to the southeast with the North Patagonian Massif and to the northeast with the San Rafael Block and to the east with the Sierra Pintada System. The basin covers an area of approximately .Howell et al., 2005 One age of the SALMA classification, the Colloncuran, is defined in the basin, based on the Collón Curá Formation, named after the Collón Curá River, a tributary of the Limay River. Description Jurassic and Cretaceous marine transgressions from the Pacific are recorded in the sediments of Neuquén Basin. These marine sediments belong to Cuyo Group, Tordillo Formation, Auquilco Formation and Vaca Muerta. In the Late Cretaceous, conditions in the neighboring Andean orogen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mendoza Province
Mendoza, officially Province of Mendoza, is a province of Argentina, in the western central part of the country in the Cuyo region. It borders San Juan to the north, La Pampa and Neuquén to the south, San Luis to the east, and the republic of Chile to the west; the international limit is marked by the Andes mountain range. Its capital city is the homonymous city of Mendoza. Covering an area of 148,827 km2, it is the seventh biggest province of Argentina with 5.35% of the country's total area. The population for 2010 is 1,741,610 inhabitants, which makes it the fourth most populated province of the country, or 4.35% of the total national population. History Pre-Columbian times Archeological studies have determined that the first inhabitants in the area date from the Holocene, but there are few remains of those people to know their habits. The earliest sites of human occupation in Mendoza Province, Agua de la Cueva and Gruta del Indio, are 12,000–13,000 years old. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rio Negro Province
Rio or Río is the Portuguese, Spanish, Italian, and Maltese word for "river". When spoken on its own, the word often means Rio de Janeiro, a major city in Brazil. Rio or Río may also refer to: Geography Brazil * Rio de Janeiro * Rio do Sul, a town in the state of Santa Catarina, Brazil Mexico * Río Bec, a Mayan archaeological site in Mexico * Río Bravo, Tamaulipas, a city in Mexico United States * Rio, a location in Deerpark, New York, US * Rio, Florida, a census-designated place in Martin County, US * Rio, Georgia, an unincorporated community in Spalding County, US * Rio, Illinois, a village in Knox County, US * Rio, Virginia, a community in Albemarle County, US * Rio, West Virginia, a village in Hampshire County, US * Rio, Wisconsin, a village in Columbia County, US * El Río, Las Piedras, Puerto Rico, a barrio * Río Arriba, Añasco, Puerto Rico, a barrio * Río Arriba, Arecibo, Puerto Rico, a barrio * Río Arriba, Fajardo, Puerto Rico, a barrio * Río Arriba, Vega Baja, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lohan Cura Formation
The Lohan Cura Formation is a geologic formation with outcrops in the Argentine provinces of Río Negro, Neuquén, and Mendoza. It is the second oldest Cretaceous terrestrial formation in the Neuquén Basin. The Lohan Cura Formation unconformably overlies the terrestrial La Amarga Formation. In some places it also overlies the older marine Agrio and Bajada Colorada Formations of the Mendoza Group through the same Middle Miranican unconformity. It is in turn overlain by the Candeleros Formation of the Neuquén Group, separated by the Main Miranican unconformity. The Lohan Cura correlates with the Rayoso Formation in some areas.Leanza et al., 2004, p.66 Subdivision The Lohan Cura Formation contains two members of roughly equal thickness. The lowermost member, Puesto Quiroga Member is approximately thick. The lowest sediments in this unit are conglomerates, overlain by sandstones and siltstones. The upper two-thirds of the member consists mainly of shales. The Cullín Grande ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
