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Picuris Orogeny
The Picuris orogeny was an orogenic event in what is now the Southwestern United States from 1.43 to 1.3 billion years ago in the Calymmian Period of the Mesoproterozoic. The event is named for the Picuris Mountains in northern New Mexico and interpreted either as the suturing of the Granite-Rhyolite crustal province to the southern margin of the proto-North American continent Laurentia or as the final suturing of the Mazatzal crustal province onto Laurentia. According to the former hypothesis, this was the second in a series of orogenies within a long-lived convergent boundary along southern Laurentia that ended with the ca. 1200–1000 Mya Grenville orogeny during the final assembly of the supercontinent Rodinia, which ended an 800-million-year episode of convergent boundary tectonism. Description Age and isotope data show that southern North America is composed of a series of northeast-trending provinces representing island arc terranes accreted onto the 1800 Mya core of Lauren ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pilar Formation Outcrop
Pilar, Portuguese and Spanish for pillar, may refer to: People * Pilar (given name), a common abbreviation of ''María del Pilar'', including a list of people so named * Pilar (surname), a list of people surnamed Pilar or del Pilar Places Argentina * Barrio El Pilar, a village and municipality in Río Negro Province * Pilar, Buenos Aires Province * Pilar, Córdoba Province * Pilar Partido, a partido located in Greater Buenos Aires in Buenos Aires Province Brazil * Pilar, Alagoas * Pilar, Paraíba * Pilar de Goiás, Goiás * Pilar do Sul, São Paulo Philippines * Pilar, Abra, a 5th class municipality * Pilar, Bataan, a 3rd class municipality * Pilar, Bohol, a 4th class municipality * Pilar, Capiz, a 4th class municipality * Pilar, Cebu, a 5th class municipality * Pilar, Sorsogon, a 1st class municipality * Pilar, Surigao del Norte, a 5th class municipality Elsewhere * El Pilar, an ancient Mayan city center on the Belize-Guatemala border * Pilar da Bretanha, a civil paris ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proterozoic
The Proterozoic () is a geological eon spanning the time interval from 2500 to 538.8million years ago. It is the most recent part of the Precambrian "supereon". It is also the longest eon of the Earth's geologic time scale, and it is subdivided into three geologic eras (from oldest to youngest): the Paleoproterozoic, Mesoproterozoic, and Neoproterozoic. The Proterozoic covers the time from the appearance of oxygen in Earth's atmosphere to just before the proliferation of complex life (such as trilobites or corals) on the Earth. The name ''Proterozoic'' combines two forms of ultimately Greek origin: meaning 'former, earlier', and , 'of life'. The well-identified events of this eon were the transition to an oxygenated atmosphere during the Paleoproterozoic; the evolution of eukaryotes; several glaciations, which produced the hypothesized Snowball Earth during the Cryogenian Period in the late Neoproterozoic Era; and the Ediacaran Period (635 to 538.8 Ma) which is characterize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rocky Mountains
The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in the southwestern United States. Depending on differing definitions between Canada and the U.S., its northern terminus is located either in northern British Columbia's Terminal Range south of the Liard River and east of the Trench, or in the northeastern foothills of the Brooks Range/ British Mountains that face the Beaufort Sea coasts between the Canning River and the Firth River across the Alaska-Yukon border. Its southernmost point is near the Albuquerque area adjacent to the Rio Grande rift and north of the Sandia–Manzano Mountain Range. Being the easternmost portion of the North American Cordillera, the Rockies are distinct from the tectonically younger Cascade Range and Sierra Nevada, which both lie farther to its west. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precambrian
The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic Eon, which is named after Cambria, the Latinised name for Wales, where rocks from this age were first studied. The Precambrian accounts for 88% of the Earth's geologic time. The Precambrian is an informal unit of geologic time, subdivided into three eons ( Hadean, Archean, Proterozoic) of the geologic time scale. It spans from the formation of Earth about 4.6 billion years ago ( Ga) to the beginning of the Cambrian Period, about million years ago ( Ma), when hard-shelled creatures first appeared in abundance. Overview Relatively little is known about the Precambrian, despite it making up roughly seven-eighths of the Earth's history, and what is known has largely been discovered from the 1960s onwards. The Precambrian fossil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
East Antarctica
East Antarctica, also called Greater Antarctica, constitutes the majority (two-thirds) of the Antarctic continent, lying on the Indian Ocean side of the continent, separated from West Antarctica by the Transantarctic Mountains. It lies almost entirely within the Eastern Hemisphere and its name has been accepted for more than a century. It is generally higher than West Antarctica and includes the Gamburtsev Mountain Range in the center. The geographic South Pole is located within East Antarctica. Apart from small areas of the coast, East Antarctica is permanently covered by ice and it has relatively low biodiversity, with only a small number of species of terrestrial plants, animals, algae, and lichens. The coasts are the breeding ground for various seabirds and penguins, and the leopard seal, Weddell seal, elephant seal, crabeater seal and Ross seal breed on the surrounding pack ice in summer. Location and description Almost completely covered in thick, permanent ice, East A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SWEAT (hypothesis)
SWEAT (which stands for Southwestern United States and East Antarctica) is the hypothesis that the Southwestern United States was at one time connected to East Antarctica. The hypothesis of a late Precambrian fit of western North America with the Australia-Antarctic shield region permits the extension of many features through Antarctica and into other parts of Gondwana. For example, the Grenville orogen may extend around the coast of East Antarctica into India and Australia, and the ophiolitic belt of the latter may extend into East Antarctica. The Wopmay orogen of northwest Canada may extend through eastern Australia into Antarctica and thence beneath the ice to connect with the Yavapai- Mazatzal orogens of the southwestern United States. Counterparts of the Precambrian-Paleozoic sedimentary rocks along the U.S. Cordilleran miogeocline may be present in the Transantarctic Mountains. Orogenic belt boundaries provide useful piercing points for Precambrian continental reconstruc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albany-Fraser Orogeny
The Albany-Fraser orogeny was an orogenic event which created the Albany-Fraser Orogen in what is now Australia between 2.63 and 1.16 billion years ago, during the late Archean and Proterozoic. Tectonic history developed from isotope dating suggests that the orogeny occurred as the combined North Australia Craton-West Australia Craton collided with the East Antarctic-South Australian Craton. The Kepa Kurl Booya Province, including its component zones, the Fraser Zone, Nornalup Zone and Biranup Zone represents the crystalline basement of the orogen. Numerous theories and hypotheses have been presented about the orogeny. For example, in 2011 geochronology dating of 1.71 to 1.65 billion year old granite and gabbro intrusions in the Biranup Zone suggested craton margin rocks rather than a previously interrupted small terrane wedged against the Yilgarn Craton. In other cases, researchers attempting to reconstruct the supercontinent Rodinia suggested a possible connection between Australi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baltica
Baltica is a paleocontinent that formed in the Paleoproterozoic and now constitutes northwestern Eurasia, or Europe north of the Trans-European Suture Zone and west of the Ural Mountains. The thick core of Baltica, the East European Craton, is more than three billion years old and formed part of the Rodinia supercontinent at 1 . Tectonic history Baltica formed at 2.0–1.7 Ga by the collision of three Archaean-Proterozoic continental blocks: Fennoscandia (including the exposed Baltic Shield), Sarmatia (Ukrainian Shield and Voronezh Massif), and Volgo-Uralia (covered by younger deposits). Sarmatia and Volgo-Uralia formed a proto-craton (sometimes called "Proto-Baltica") at c. 2.0 Ga which collided with Fennoscandia c. 1.8–1.7 Ga. The sutures between these three blocks were reactivated during the Mesoproterozoic and Neoproterozoic. 750–600 million years ago, Baltica and Laurentia rotated clockwise together and drifted away from the Equator towa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norwegian Journal Of Geology
''Norwegian Journal of Geology'' ( no, Norsk Geologisk Tidsskrift) is a quarterly peer-reviewed scientific journal published by the Norwegian Geological Society. The scope of the journal is the geology of Norway, the Arctic, and nearby seas. The journal adopted the Creative Commons Attribution License for published works since volume 94, issue 4 (2014). Abstracting and indexing The journal is abstracted and indexed in: See also * ''Fennia'' *''Geografiska Annaler'' *''Norwegian Journal of Geography __NOTOC__ ''Norwegian Journal of Geography'' ( no, Norsk Geografisk Tidsskrift) is a peer-reviewed scientific journal published by Routledge on behalf of the Norwegian Geographical Society. It covers geographical topics of interest to Norwegian res ...'' References External links * Geology journals Multilingual journals Norwegian-language journals English-language journals 1905 establishments in Norway Publications established in 1905 Quarterly journals Creative C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gothian Orogeny
The Gothian orogeny ( sv, Gotiska orogenesen) or Kongsberg orogeny was an orogeny in western Fennoscandia that occurred between 1750 and 1500 million years ago. It precedes the younger Sveconorwegian orogeny that has overprinted much of it. The Gothian orogeny formed along a subduction zone and resulted in the formation of calc-alkaline igneous rocks 1700 to 1550 million years ago, including some of the younger members of the Transscandinavian Igneous Belt. The deformation associated with the orogeny can be seen in metatonalite, paragneiss and biotite orthogneisses in southeast Norway. These rocks were all subject to amphibolite facies metamorphism Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of ch .... Footnotes References * * {{Geology of Europe Orogenies of Europe Paleop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleomagnetism
Paleomagnetism (or palaeomagnetismsee ), is the study of magnetic fields recorded in rocks, sediment, or archeological materials. Geophysicists who specialize in paleomagnetism are called ''paleomagnetists.'' Certain magnetic minerals in rocks can record the direction and intensity of Earth's magnetic field at the time they formed. This record provides information on the past behavior of the geomagnetic field and the past location of tectonic plates. The record of geomagnetic reversals preserved in volcanic and sedimentary rock sequences (magnetostratigraphy) provides a time-scale that is used as a geochronologic tool. Evidence from paleomagnetism led to the revival of the continental drift hypothesis and its transformation into the modern theory of plate tectonics. Apparent polar wander paths provided the first clear geophysical evidence for continental drift, while marine magnetic anomaly, magnetic anomalies did the same for seafloor spreading. Paleomagnetic data continues t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neoproterozoic
The Neoproterozoic Era is the unit of geologic time from 1 billion to 538.8 million years ago. It is the last era of the Precambrian Supereon and the Proterozoic Eon; it is subdivided into the Tonian, Cryogenian, and Ediacaran periods. It is preceded by the Mesoproterozoic Era and succeeded by the Paleozoic Era of the Phanerozoic Eon. The most severe glaciation known in the geologic record occurred during the Cryogenian, when ice sheets may have reached the equator and formed a " Snowball Earth". The earliest fossils of complex multicellular life are found in the Ediacaran Period. These organisms make up the Ediacaran biota, including the oldest definitive animals in the fossil record. According to Rino and co-workers, the sum of the continental crust formed in the Pan-African orogeny and the Grenville orogeny makes the Neoproterozoic the period of Earth's history that has produced most continental crust. Geology At the onset of the Neoproterozoic the supercontine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
