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Alvarez Hypothesis
The Alvarez hypothesis posits that the mass extinction of the non-avian dinosaurs and many other living things during the Cretaceous–Paleogene extinction event was caused by the impact of a large asteroid on the Earth. Prior to 2013, it was commonly cited as having happened about 65 million years ago, but Renne and colleagues (2013) gave an updated value of 66 million years. Evidence indicates that the asteroid fell in the Yucatán Peninsula, at Chicxulub, Mexico. The hypothesis is named after the father-and-son team of scientists Luis and Walter Alvarez, who first suggested it in 1980. Shortly afterwards, and independently, the same was suggested by Dutch paleontologist Jan Smit. In March 2010, an international panel of scientists endorsed the asteroid hypothesis, specifically the Chicxulub impact, as being the cause of the extinction. A team of 41 scientists reviewed 20 years of scientific literature and in so doing also ruled out other theories such as massive volcanism. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LWA With Walt
( ), also called loa or loi, are spirits in the African diasporic religion of Haitian Vodou. They have also been incorporated into some revivalist forms of Louisiana Voodoo. Many of the lwa derive their identities in part from deities venerated in the traditional religions of West Africa, especially those of the Fon and Yoruba. In Haitian Vodou, the lwa serve as intermediaries between humanity and Bondyé, a transcendent creator divinity. Vodouists believe that over a thousand lwa exist, the names of at least 232 of which are recorded. Each lwa has its own personality and is associated with specific colors and objects. Many of them are equated with specific Roman Catholic saints on the basis of similar characteristics or shared symbols. The lwa are divided into different groups, known as ''nanchon'' (nations), the most notable of which are the Petwo and the Rada. According to Vodou belief, the lwa communicate with humans through dreams and divination, and in turn are gi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frank Asaro
Frank Asaro (born Francesco Asaro, July 31, 1927 – June 10, 2014) was an Emeritus Senior Scientist at the Lawrence Berkeley National Laboratory associated with the University of California at Berkeley. He is best known as the chemist who discovered the iridium anomaly in the Cretaceous–Paleogene boundary layer that led the team of Luis Alvarez, Walter Alvarez, Frank Asaro, and Helen Michel to propose the Asteroid-Impact Theory, which postulates that an asteroid hit the Earth sixty-five million years ago and caused mass extinction during the age of the dinosaurs. Biography Asaro grew up in Escondido, California, the son of avocado farmer and barber Nicolo Asaro and Antonina (Annie) Asaro. He married Lucille Marie Lavezo and settled in the California Bay Area. They had four children, Frank, Antonina, Catherine, and Marianna. Asaro's mother, one of the oldest known residents of Escondido, lived until almost 106 years old. Research The Early Berkeley Years Asaro went to c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tektite
Tektites (from grc, τηκτός , meaning 'molten') are gravel-sized bodies composed of black, green, brown or grey natural glass formed from terrestrial debris ejected during meteorite impacts. The term was coined by Austrian geologist Franz Eduard Suess (1867–1941), son of Eduard Suess. They generally range in size from millimetres to centimetres. Millimetre-scale tektites are known as microtektites.French, B. M. (1998) ''Traces of Catastrophe: A Handbook of Shock-Metamorphic Effects in Terrestrial Meteorite Impact Structures.'' LPI Contribution No. 954. Lunar and Planetary Institute, Houston, Texas. 120 pp.McCall, G. J. H. (2001) ''Tektites in the Geological Record: Showers of Glass from the Sky.'' The Geological Society Publishing House, Bath, United Kingdom. 256 pp. Montanari, A., and C. Koeberl (2000) ''Impact Stratigraphy. The Italian Record.'' Lecture Notes in Earth Sciences Series no. 93. Springer-Verlag, New York, New York. 364 pp. Tektites are characterized by: # ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tanis (fossil Site)
Tanis is a site of paleontological interest in southwestern North Dakota, United States. Tanis is part of the heavily studied Hell Creek Formation, a group of rocks spanning four states in North America renowned for many significant fossil discoveries from the Upper Cretaceous and lower Paleocene. Tanis is a significant site because it appears to record the events from the first minutes until a few hours after the impact of the giant Chicxulub asteroid in extreme detail. This impact, which struck the Gulf of Mexico 66.043 million years ago, wiped out all non-avian dinosaurs and many other species (the so-called "K-Pg" or "K-T" extinction). The extinction event caused by this impact began the Cenozoic, in which mammals - including humans - would eventually come to dominate life on Earth. Discoveries The site was originally discovered in 2008 by University of North Georgia Professor Steve Nicklas and field paleontologist Rob Sula. Their team successfully removed fossil field ja ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PNAS
''Proceedings of the National Academy of Sciences of the United States of America'' (often abbreviated ''PNAS'' or ''PNAS USA'') is a peer-reviewed multidisciplinary scientific journal. It is the official journal of the National Academy of Sciences, published since 1915, and publishes original research, scientific reviews, commentaries, and letters. According to ''Journal Citation Reports'', the journal has a 2021 impact factor of 12.779. ''PNAS'' is the second most cited scientific journal, with more than 1.9 million cumulative citations from 2008 to 2018. In the mass media, ''PNAS'' has been described variously as "prestigious", "sedate", "renowned" and "high impact". ''PNAS'' is a delayed open access journal, with an embargo period of six months that can be bypassed for an author fee (hybrid open access). Since September 2017, open access articles are published under a Creative Commons license. Since January 2019, ''PNAS'' has been online-only, although print issues are av ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SF Gate
The ''San Francisco Chronicle'' is a newspaper serving primarily the San Francisco Bay Area of Northern California. It was founded in 1865 as ''The Daily Dramatic Chronicle'' by teenage brothers Charles de Young and Michael H. de Young. The paper is owned by the Hearst Corporation, which bought it from the de Young family in 2000. It is the only major daily paper covering the city and county of San Francisco. The paper benefited from the growth of San Francisco and had the largest newspaper circulation on the West Coast of the United States by 1880. Like other newspapers, it experienced a rapid fall in circulation in the early 21st century and was ranked 18th nationally by circulation in the first quarter of 2021. In 1994, the newspaper launched the SFGATE website, with a soft launch in March and official launch November 3, 1994, including both content from the newspaper and other sources. "The Gate" as it was known at launch was the first large market newspaper website in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ar-Ar Dating
Arar or Ar-Ar may refer to: Geography and history * Arar, Saudi Arabia, the capital of Al Hudud ash Shamaliyah (The Northern Border) province ** Arar border crossing, a Saudi-Iraqi border crossing near Arar, Saudi Arabia and Nukhayb, Iraq * Arar, Pakistan, a village in Sargodha District, Pakistan * Saône, a river in eastern France, formerly known as Arar * Battle of the Arar, a battle between the Romans and the Helvetii in 58 BC People * Ege Arar (born 1996), Turkish basketball player * Funda Arar (born 1975), Turkish singer * Maher Arar (born 1970), Canadian-Syrian engineer, deported from the US ** '' Arar v. Ashcroft'', a legal case brought by Maher Arar * Mustafa Wahbi al-Tal (1897–1949), Jordanian poet nicknamed Arar * Taleb Abu Arar (born 1967), Bedouin Israeli Arab politician Science * Argon–argon dating Argon–argon (or 40Ar/39Ar) dating is a radiometric dating method invented to supersede potassiumargon (K/Ar) dating in accuracy. The older method required sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Berkeley Geochronology Center
The Berkeley Geochronology Center (BGC) is a non-profit geochronology research institute in Berkeley, California. It was originally a research group in the laboratory of geochronologist Garniss Curtis at the University of California, Berkeley. The center is now an independent scientific research institute with close Berkeley affiliations and directed by geologist and geochronologist Paul Renne, a professor in residence in the department of earth and planetary science at Berkeley. History In 1985, Curtis, set to retire in 1989, moved the group from his lab at the university to the basement of the independent Institute for Human Origins (IHO), at the suggestion of American anthropologist F. Clark Howell. The geochronologists worked separately from the IHO, although IHO contained their bureaucratic infrastructure, until 1989 when they became officially known as the Institute for Human Origins Geochronology Center. In 1994 the group officially split from the IHO based on differen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Renne
Paul R. Renne (born 1957 in San Antonio, Texas) is the director of the Berkeley Geochronology Center and also Professor in Residence of geology in the Department of Earth & Planetary Science, University of California, Berkeley (UC Berkeley). Renne is considered a leading expert on the argon–argon dating technique and is interested in paleomagnetism in Earth history, precisely dating flood basalts, particularly the Siberian Traps, and large igneous province volcanism in general, and paleoanthropology Paleoanthropology or paleo-anthropology is a branch of paleontology and anthropology which seeks to understand the early development of anatomically modern humans, a process known as hominization, through the reconstruction of evolutionary kinsh .... Renne received his A.B. and his Ph.D. in geology from UC Berkeley. References Radiometric dating Living people 1957 births People from San Antonio American geologists University of California, Berkeley alumni Universit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinction Of The Dinosaurs
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. More than 99% of all species that ever lived on Earth, amounting to over five billion species, are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryote globally, and possibly many times more if microorganisms, like bacteria, are included. Notable extinct animal species include non-avian dinosaurs, saber-toothed cats, dodos, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iridium
Iridium is a chemical element with the symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, it is considered the second-densest naturally occurring metal (after osmium) with a density of as defined by experimental X-ray crystallography. It is one of the most corrosion-resistant metals, even at temperatures as high as . However, corrosion-resistance is not quantifiable in absolute terms; although only certain molten salts and halogens are corrosive to solid iridium, finely divided iridium dust is much more reactive and can be flammable, whereas gold dust is not flammable but can be attacked by substances that iridium resists, such as aqua regia. Iridium was discovered in 1803 among insoluble impurities in natural platinum. Smithson Tennant, the primary discoverer, named it after the Greek goddess Iris, personification of the rainbow, because of the striking and diverse colors of its salts. Iridium is one of the rarest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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