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Gaskiers Glaciation
The Gaskiers glaciation is a period of widespread glacial deposits (e.g. diamictites) that lasted under 340 thousand years, between 579.63 ± 0.15 and 579.88 ± 0.44 million years ago — i.e. late in the Ediacaran Period — making it the last major glacial event of the Precambrian.F. M. Gradstein, Gabi Ogg, Mark Schmitz, ''The Geologic Time Scale'', Elsevier, 2012, p. 428. It was also the last and the shortest of at least three major ice ages in the Neoproterozoic era. It is assumed that, in contrast to the Sturtian and Marinoan periods, it did not lead to global glaciation ("Snowball Earth"). Deposits attributed to the Gaskiers — assuming that they were all deposited at the same time — have been found on eight separate paleocontinents, in some cases occurring close to the equator (at a latitude of 10–30°). The 300 m-thick name-bearing section at Gaskiers (Newfoundland) is packed full of striated dropstones. Its values are very low (pushing ), consistent with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacial Deposit
image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is diagnostic of till. image:Glacial till exposed in roadcut-750px.jpg, Glacial till with tufts of grass Till or glacial till is unsorted glacier, glacial sediment. Till is derived from the erosion and entrainment of material by the moving ice of a glacier. It is deposited some distance down-ice to form terminal, lateral, medial and ground moraines. Till is classified into primary deposits, laid down directly by glaciers, and secondary deposits, reworked by fluvial transport and other processes. Description Till is a form of '' glacial drift'', which is rock material transported by a glacier and deposited directly from the ice or from running water emerging from the ice. It is distinguished from other forms of drift in that it is dep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gaskiers-Point La Haye
Gaskiers-Point La Haye is a town in Newfoundland and Labrador, Canada, located in St. Mary's Bay. It is located southwest of St. Mary's. It became a local government community in 1970. In 2021, the town had a population of 189. Demographics In the 2021 Census of Population conducted by Statistics Canada, Gaskiers-Point La Haye had a population of living in of its total private dwellings, a change of from its 2016 population of . With a land area of , it had a population density of in 2021. Local attractions Hare Hill Trail (Point La Haye) is a well-developed trail that was originally used by wood cutters, hunters and berry pickers for centuries. The trail is a total of three kilometres long and reaches an elevation of 135 m at its highest point. Upon reaching the top, there is a view of many communities in St. Mary's Bay. Towns and communities nearby * Admiral's Beach * Mosquito * St. Mary's * St. Vincent's-St. Stephen's-Peter's River * Riverhead See also * St ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ediacaran Geology
The Ediacaran Period ( ) is a geological period that spans 96 million years from the end of the Cryogenian Period 635 million years ago (Mya), to the beginning of the Cambrian Period 538.8 Mya. It marks the end of the Proterozoic Eon, and the beginning of the Phanerozoic Eon. It is named after the Ediacara Hills of South Australia. The Ediacaran Period's status as an official geological period was ratified in 2004 by the International Union of Geological Sciences (IUGS), making it the first new geological period declared in 120 years. Although the period takes its name from the Ediacara Hills where geologist Reg Sprigg first discovered fossils of the eponymous Ediacaran biota in 1946, the type section is located in the bed of the Enorama Creek within Brachina Gorge in the Flinders Ranges of South Australia, at . The Ediacaran marks the first appearance of widespread multicellular fauna following the end of Snowball Earth glaciation events, the so-called Ediacaran biota, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precambrian Research
''Precambrian Research'' is a peer-reviewed scientific journal covering the geology of the Earth and its planetary neighbors. It is published by Elsevier and, , the editors-in-chief are V. Pease (Stockholm University) and G.C. Zhao (University of Hong Kong). It was established in 1974. According to the ''Journal Citation Reports'', the journal has a 2013 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 6.023. References External links * * Geology journals Elsevier academic journals English-language journals Publications established in 1974 {{geology-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
West African Craton
The West African Craton (WAC) is one of the five cratons of the Precambrian basement rock of Africa that make up the African Plate, the others being the Kalahari craton, Congo craton, Saharan Metacraton and Tanzania Craton.Jessell M.W., Liégeois J-P. (2015). "100 years of research on the West African Craton". ''Journal of African Earth Sciences''. 112(B): 377– 381. Cratons themselves are tectonically inactive, but can occur near active margins,Ennih N. & Liégeois J-P. (2008). ''The Boundaries of the West African Craton''. Geological Society, London, Special Publications. 297: 1–17. with the WAC extending across 14 countries in Western Africa, coming together in the late Precambrian and early Palaeozoic eras to form the African continent. It consists of two Archean centers juxtaposed against multiple Paleoproterozoic domains made of greenstone belts, sedimentary basins, regional granitoid-tonalite-trondhjemite-granodiorite, tonalite-trondhjemite-granodiorite (TTG) plutons, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is Earth's most abundant element, and after hydrogen and helium, it is the third-most abundant element in the universe. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula . Diatomic oxygen gas currently constitutes 20.95% of the Earth's atmosphere, though this has changed considerably over long periods of time. Oxygen makes up almost half of the Earth's crust in the form of oxides.Atkins, P.; Jones, L.; Laverman, L. (2016).''Chemical Principles'', 7th edition. Freeman. Many major classes of organic molecules in living organisms contain oxygen atoms, such as proteins, nucleic acids, carbohydrates, and fats, as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ediacaran Biota
The Ediacaran (; formerly Vendian) biota is a Taxonomy (biology), taxonomic period classification that consists of all life forms that were present on Earth during the Ediacaran Period (). These were composed of enigmatic tubular and frond-shaped, mostly sessility (zoology), sessile, organisms. Trace fossils of these organisms have been found worldwide, and represent the earliest known complex multicellular organisms. The Ediacaran biota may have undergone evolutionary radiation in a proposed event called the Avalon explosion, . This was after the Earth had thawed from the Cryogenian period's Snowball Earth, extensive glaciation. This biota largely disappeared with the rapid increase in biodiversity known as the Cambrian explosion. Most of the currently existing body plans of animals first appeared in the fossil, fossil record of the Cambrian rather than the Ediacaran. For macroorganisms, the Cambrian biota appears to have almost completely replaced the organisms that dominate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dropstone
Dropstones are isolated fragments of rock found within finer-grained water-deposited sedimentary rocks or pyroclastic beds. They range in size from small pebbles to boulders. The critical distinguishing feature is that there is evidence that they were not transported by normal water currents, but rather dropped in vertically through the air or water column. Such deposition can occur i.e. during a volcanic eruption. Background When deposited into fine layered mud, such evidence includes an impact depression beneath the dropstone, and indication that the mud has been squeezed up around the edges of the falling rock. Subsequent deposits of mud drape over the dropstone and its crater. Glacial dropstones, involving rocks falling out of icebergs, are one of the most common types of dropstone preserved in the geological record, particularly when deposited in low-energy deep sea or lake environments. Dropstones differ from erratics found in glacial till in that they are deposited in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equator
The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can also be used for any other celestial body that is roughly spherical. In spatial (3D) geometry, as applied in astronomy, the equator of a rotating spheroid (such as a planet) is the parallel (circle of latitude) at which latitude is defined to be 0°. It is an imaginary line on the spheroid, equidistant from its poles, dividing it into northern and southern hemispheres. In other words, it is the intersection of the spheroid with the plane perpendicular to its axis of rotation and midway between its geographical poles. On and near the equator (on Earth), noontime sunlight appears almost directly overhead (no more than about 23° from the zenith) every day, year-round. Consequently, the equator has a rather stable daytime temperature throug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diamictite
Diamictite (; from Ancient Greek ''δια'' (dia-): ''through'' and ''µεικτός'' (meiktós): ''mixed'') is a type of lithified sedimentary rock that consists of nonsorted to poorly sorted terrigenous sediment containing particles that range in size from clay to boulders, suspended in a matrix of mudstone or sandstone. The term was coined by Richard Foster Flint and others as a purely descriptive term, devoid of any reference to a particular origin.Flint, R.F., J.E. Sanders, and J. Rodgers (1960) ''Diamictite, a substitute term for symmictite'' Geological Society of America Bulletin. 71(12):1809–1810. Some geologists restrict the usage to nonsorted or poorly sorted conglomerate or breccia that consists of sparse, terrigenous gravel suspended in either a mud or sand matrix. Tucker, M.E. (2003) ''Sedimentary Rocks in the Field'' John Wiley & Sons, Ltd., New York, New York. 244 pp. Unlithified diamictite is referred to as diamicton. The term diamictite is often applied t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleocontinent
A paleocontinent or palaeocontinent is a distinct area of continental crust that existed as a major landmass in the geological past. There have been many different landmasses throughout Earth's time. They range in sizes, some are just a collection of small microcontinents while others are large conglomerates of crust. As time progresses and sea levels rise and fall more crust can be exposed making way for larger landmasses. The continents of the past shaped the evolution of organisms on Earth and contributed to the climate of the globe as well. As landmasses break apart, species are separated and those that were once the same now have evolved to their new climate. The constant movement of these landmasses greatly determines the distribution of organisms on Earth's surface. This is evident with how similar fossils are found on completely separate continents. Also, as continents move, mountain building events (orogenies) occur, causing a shift in the global climate as new rock is expo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snowball Earth
The Snowball Earth hypothesis proposes that, during one or more of Earth's Greenhouse and icehouse Earth, icehouse Climate, climates, the Earth's surface, planet's surface became entirely or nearly entirely Freezing, frozen. It is believed that this occurred sometime before 650 M.Y.A. (million years ago) during the Cryogenian period. Proponents of the hypothesis argue that it best explains sedimentary Deposition (geology), deposits that are generally believed to be of glacial origin at tropical palaeolatitudes and other enigmatic features in the geological record. Opponents of the hypothesis contest the geological evidence for Glacial period, global glaciation and the geophysical feasibility of an ice- or slush-covered ocean, and they emphasize the difficulty of escaping an all-frozen condition. A number of unanswered questions remain, including whether Earth was a full snowball or a "slushball" with a thin Equator, equatorial band of open (or seasonally open) water. The snowball ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
